When the engine idles, there will usually be a misfire that you can feel just from holding onto the steering wheel. 2006 Road King fuel injected, no modifications. Engine load stayed low at12-13%. It will rerpeat this randomly. Exterior Features; Bodyside/Cab Step or Running Board: Option; Bumper Step Up: Standard; Front Air Dam: Standard; Metallic Paint: Standard; Power Sliding Side Van Door: N/A; Power. It only happens once it gets warm. If I keep it from reaching that low of an rpm, it runs perfect. 1994 mustang gt misfire: Engine 1994 mustang gt Rough idle, misfire under acceleration: Weird idle or when engine hot running. RE: Very rough idle when stopped IP: Logged Message: "Detori, I'm on my third dakota, the rough idle just comes with age. Hey guys i have a 95 tahoe and it just started running rough lately. The car started and everything was find at first then started rough idle only on idle and pulled out of it as I pressed the gas pedal. To diagnose, first perform a slow neutral run up in park/neutral. Joined Dec 10 based on engine rpm and load, a fault is set. A rough idling engine can be caused by spark plugs or spark plug wires. If your car has a rough idle, it may be because your idle speed setting is incorrect. Exterior; Chrome front and rear bumpers; Conventional lens halogen bulb headlights; Courtesy lights; Gloss paint , black paint , metallic paint; Rear platform step; Heating, Venti. I know it's not just the guage because the engine clearly is review up and down with it. Any mustang guru's have some input? I'm absolutely stumped. Symptoms seem worse when engine is cold. Can low idle speed cause this too? Answer Why would my 2004 Mustang GT develope a. rough running between 1000. Lean misfire can also be caused by an EGR valve that is stuck open or is not closing fully. Almsot like a vacuum leak rough idle. 3 is now 4 months old and has done almost 5000 km. P1460 With Constant Control Relay Module (CCRM). i took it to a ford dealer and that was the fix. increase right off idle helps considerably with the initial launch. My dealer tells me it is normal for ten speeds to act this way. As far as the shaking goes it sounds like a misfire. Re: Misfire when started, NO IDLE Fuel Pressure is good, Throttle Body is clean, I found online that the IAC gets stuck from carbon buildup, so we cleaned it, it idles great, and starts good too, we also found that the cruise control cable was holding the throttle partially open. Okay, I've been reading since I got my WRX, about the rough idle issues. P0316 Engine Misfire at Startup OBD-II Trouble Code Technical Description. Very rough idle, very erratic rpm, then would quit. Felt like a misfire, so I replaced plugs and wires. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc. Not only that, but quite a few things can cause a misfire condition (or misfire trouble codes). Replaced fuel pump motor only, cleaned tank changed fuel filter and it ran great for about 60 miles. 1997 Ford Escort LX Sedan. Plugs have been gapped at. Is this due to it being ritch? Do I need to just lean out the low speed needle? I think the high speed needle will need leaned out too after a few tanks to get the peak rpm. It's been -15C to -20C all week and -30C here this morning. On 1996 and newer vehicles that are OBD II compliant and have misfire detection, OBD II tracks and counts misfires. 98 contour 2. From what I've been told is that these engines are notorious for having intake manifold leaks so I went ahead and changed out the intake manifold gaskets and headgaskets since it's been a very long time. More than half the time, but not all the time, at low RPM and light throttle, I have a bad "miss. how to adjust idle on 1992 mustang 5. Unrelated to the shaking and misfire code, your truck will still probably start rough in the mornings. As far as the shaking goes it sounds like a misfire. Your problem is a misfire. The car started to idle rough and occasionally surge at a stop, it would drop below 500 rpm then shoot up to around 1200-1400 rpm but if I gave it a little throttle it would clear up. Exhaust didn't seem to be an issue because high rpm power and performance was excellent. Or, it may start and idle fine but then misfire or hesitate when it comes under load. Car will shake. Sometimes the engine will misfire on Idle also, and your engine sensors will get faulty values, and the air-fuel mixture will get messed up. The car also is running rich. As everything in my life my car broke down in a super complicated way and no repair shop can diagnose my problem. It seems to stumble a little bit at low RPM. Rough Idle When Starting Cold, Then Goes Away When Engine Is At Operating Temperature More Details Below I have an older, low mileage vehicle with a V8 engine. Misfires are probably one of the most common reasons when it comes to rough idle. 0 its idle real low at like. 93 will varnish up injectors as easily as 87. Replaced fuel pump motor only, cleaned tank changed fuel filter and it ran great for about 60 miles. Ever since I bought my 89 5. 2005 Ford F150 stalls at idle and surges Recently we came across a 2005 Ford F150 with a 5. Anyone know where I can find a diagram or other thoughts? Thanks. Any clue on possible cause?. 6L Rough Idle/misfire. I've had problems recently with my '03 vibe running real rough. 0 and ford motors for matter. No, if you up the idle manually, the ECU will eventually reset itself and bring your idle back down to being too low. Ford Mustang V6 2005-2014: Why is My Check Engine Light Flashing? A flashing check engine light is a good reason to worry. 2006 Mustand GT. As the engine warms up, the problem fades and is much less noticeable. The setup is currently not controlling timing, running only a mechanical advance distributor. Following are a few key points about Ford misfire monitoring found in these documents: •The Fuel Tank level must be above 15% for misfire monitor operation. The intake manifold O-ring gaskets commonly leak, which creates a large vacuum leak. The number one cause for high idle is an imbalance in air pressure. My Volkswagen has a six speed auto, and i think I turn 2000 RPM at 65 mph, and a tad more at 70. 2), one day they run normal, and the next day its runnin rough-fuel. There is an idle circuit in the rear barrels of your Holley, too. RPMs will fluctuate quite a bit and then settle down. My car was running perfectly until I disconnected the negative battery terminal to install fog light bulbs. The 1-6 in the powertrain codes, indicate which. Enhanced Porsche Engine Module List - autoenginuity ,AutoEnginuity OBD2 (OBDII) Scan Tool is a professional Windows-PC diagnostics scan tool for all OBD2 (OBDII) compliant vehicles. When revs are at about 1500rpm, I put my foot down say 20% throttle, it misfires once or twice until revs climb to 2500rpm, then will rev without missing all the way to redline. This setting can be easily reset using a butterknife or similar tool. Okay guys, so I'll cut right to the chase. Dealer says " yes its rough, but its ok with Ford". They are currently at. 60 with similar if not identical results. I did the usual and got some new premium fuel in it and added cleaner. 2004 Ranger 3. I thought it may be a misfire but not sure. I've got a 97 silverado with a 5. My check engine light came on about a week ago and i brought it to the parts store because they do the diagnostic test for free. Low RPM could indicate a clogged fuel filter, low gas, dirty or bad fuel injectors. from what i heard its because the ac compressor needs extra power so the IAC tries to get the idle to go higher but since it doesn't work like it suppose too it makes the rpms go up and down real bad, when i turn the ac on when im idling the rpms go up but and down but it doesn't get real low it gos from normal about 800 rpms to 1000 rpms and lower. If there are misfire codes stored, you will also want to diagnose and repair those prior to diagnosing a P050D. 2005 ford mustang rough idle was created by stwarrior23 So im new to this forum, but have been to plenty of mustang forums with this problem. Try cleaning injectors and throttle body and intake system and see if problem improves. The setup is currently not controlling timing, running only a mechanical advance distributor. It turned out to be multiple misfires 2004 Mustang GT: Rough/low idle and slight jerking when driving in and the car has dropped rpm so low it has stalled out. Random Misfire problem. Turned it on and everything seemed normal, no weird noises or rough idle. I drive a 1997 ford Mustang v6, when I'm in idle the rpm guage goes up and down between 1 and the half mark. Goes away completely above about 2200. low and rough idle and stalling at complete stops. Car cold starts and idles good until the idle comes down to 800 rpm then it starts to shake (very noticeable) and you can hear some sort of pop on the exhaust. Runs better, but still a little rough at low RPM. Unstable idle speed. What is a normal vacuum reading at idle for a typical Heads/cam/intake 5. When the engine is at low RPM, anything below 2K it's an intermittent mis that can be pretty violent unless I ease off the throttle. Is Check Engine Light still On/Flashing. I bought this clean 99 GT and there was a minor low rpm misfire but that was the only thing wrong. At IDLE, there should not be any more than 5. I'm thinking a clogged fuel injector as the common denominator from those codes. Car drives great at higher RPMs but under 2k rpms will misfire and at idle will drop really low 400-500 area almost where it. This started while driving in the mountains. Exterior; Chrome front and rear bumpers; Conventional lens halogen bulb headlights; Courtesy lights; Metallic paint , black paint , gloss paint; Rear platform step; Heating, Venti. What complicates a rough idle/misfire condition is having the PCM not register any specific misfire codes. They called techs at Dodge, who suggested the low idle was likely a software issue but otherwise the car was fine and that the thump/vibration may be the exhaust being rough due to the low RPM. [2000 Mustang GT] Rough idle with P0443 and other codes I recently bought a 2000 Mustang GT and although its been running, the rpm needle often moves around by a couple hundred rpms while idling, the car shakes more, and the engine begins to sound like it might die. Performed a cylinder contribution test and found all cylinders contributing at idle. The rough idle isn't as bad as the first time the rough idle occurred and is fine above 800 rpm in park. engine speed at low idle and high idle is controlled by a. The past month has been really Bad. it runs fine when i first start it, but soon idles low/rough, but only in gear. As everything in my life my car broke down in a super complicated way and no repair shop can diagnose my problem. Seems to run lean, but o2 sensors show rich code. RPMs will fluctuate quite a bit and then settle down. The coupe with the 351 Cleveland I just picked up, when its idling it idles rough and raises the RPM off and on but sort of in a pattern, when I'm driving it seems like it surges between 40-45. The pintle is free and moves. Checked plug/cop and it seems to be fine. The machine told me to replace my 02 sensor on bank 2 (passenger side) so i did. Sometime the OD OFF light comes on while the car's shaking, but not often. 2), one day they run normal, and the next day its runnin rough-fuel. (no more than 100-150 rpm. Check engine light and trouble code P0300 misfire. 6L Rough Idle/misfire. Check engine light code said misfire on cylinder 5my daughters moth. The car started and everything was find at first then started rough idle only on idle and pulled out of it as I pressed the gas pedal. When the code P0300 is set in the Power Train Computer, it means that the Misfire Monitor has detected more than a 2 percent variance in RPM between the firing of any two (or more) cylinders in the firing order. Misfire is a lot more likely to occur after the engine reaches normal operating temperature but I have witnessed cases in which a misfire could only be detected during cold start conditions. I checked everything and everything seems to be secure and in place. I wish I could make the noise for you. I checked the fuel pressure at idle, it's 32 psi. The only way to kill the engine its to choke it or pull a plug on the ignition coil and I've let it go a good 20 min after turning it off. Engine 1994 mustang gt Rough idle, misfire under acceleration: Engine '93 running rough, especially at low rpm's and idle. if you PB Blast it or some WD40 and scrape off the carbon it may fix your problem. It will go from normal to a low idlenot a rough idle and it doesn't act like it's going to shut off but a definite low idleprob around 350-400 RPM. The misses still happen as I speed up, just not as apparent. Sometimes the engine will misfire on Idle also, and your engine sensors will get faulty values, and the air-fuel mixture will get messed up. Jump to Latest Follow 1 - 13 of 13 Posts (2. The blinking would stop after a few minutes and the light would go away. 6 engine codeY. The intake manifold O-ring gaskets commonly leak, which creates a large vacuum leak. If your car, truck, or SUV doesn’t run up to snuff, you can pull off to the side of the road and call for towing assistance. It looses lots of power and slows down. Once it begins to idle back up the idle goes back smooth. I have a Code P0300 which is a Random Misfire Code. It usually causes a rough idle and the check engine light will eventually come on. but runs perfect after 4k rpm. " This would be mixture leaning out, or the spark becoming intermittent. Every morning when I go to start my car it idle pretty rough for a few seconds then its fine. I have a rough, low idle "about 700 rpms" although the inductive timing light says otherwise. Hey guys I'm having a problem (not all the time) when I have my truck at idle or under 1000 Rpms it seems to idle rough, nothing crazy just slightly b 3. Got in the car this morning and noticed a check engine light. My issue I'm having is getting the idle to smooth out and hold what I have set. I bought this clean 99 GT and there was a minor low rpm misfire but that was the only thing wrong. This can cause a very uneven idle which can jump up and down and the engine may also shut off on idle. Engine Performance Troubleshooting Tree - ISX15 CM2250 This troubleshooting procedure should be followed for the following symptoms: • Engine Acceleration or Response Poor • Engine Difficult to Start or Will Not Start • Engine Power Output Low • Engine Runs Rough at Idle • Engine Runs Rough or Misfires • Engine Speed Surges at Low. Idle problems may originate in a worn out component, a. i own a 2001 v8 tundra with 67k miles. Alloytec Misfire- Mechanic and Autoelec MUST read. I do some more research, and try cleaning my MAF. rough idle, engine dies 5 Answers. Idle is most rough, when the engine is first started in the a. You get it up to about 1k RPM and everything is great. We'll walk you through how to properly diagnose and fix a flashing check engine light. The feeling is vey similar to the sensation of a tire out of balance. Rough/shaky idle fix? Fixed stalling, missing, rough idle, surprise result. My car (94 E320-115K miles) developed a low rpm misfire. Exterior; Fog lamps; Vinyl upper/anti-scuff lower door trim w/integral armrest, map pocket, door pull handle, courtesy lights; Instrumentation; Auxiliary pwr point in instrument p. Rubber was rotted at bottom causing a vacuum leak (, rough idle). If you do not, raise the low idle speed to this range. 8l E-150 No check engine light. It also idles rough aftter getting off of the hiway and having to sit a a red light. no check engine light is on. Replaced wires, cap, rotor, plugs, coil, and TFI control module. Having a a major dilema with a rough idle / Multiple Cylinder Misfire on my 2001 Chevy S10. view more Car rough idling causes and how to fix it - 460 Ford Forum. Mine idles a little rough too it drops maybe 50 rpm once in a while usually cold starts which in my eyes are normal ( I am by far no mechanic and this is my first new and first truck) That being said. You could. Damage to the car's carburetor and vacuum hoses can cause the engine to misfire, resulting in a rough idle. The car started to idle rough and occasionally surge at a stop, it would drop below 500 rpm then shoot up to around 1200-1400 rpm but if I gave it a little throttle it would clear up. I would also recommend cleaning the throttle body. 1988 mustang GT Rough idle and misfire under load code 44/94 I'm having an issue that started about 3 weeks ago. Ahh the joys of Land Rover. I have a 66 mustang with a 289 4. The Misfire Monitor constantly checks the rotational speed of the Crankshaft by counting the pulses of the Crankshaft Sensor. >"The engine usually runs fine at idle with an occasional misfire (rarely). When i first bought this car it had a idle rough,misfire and. Re: Misfire or rough idle 1994 5. I used an ease out and replaced plug. what could be the problem. 3 is now 4 months old and has done almost 5000 km. If the vehicle is equipped with On-Board Diagnostic (OBD), a MIL illumination may also have occurred due to Diagnostic Trouble Code (DTC) P0300 - Multiple Cylinder Misfire. Recently started having a problem with - Ford 2006 Mustang question. Hey guys i have a 95 tahoe and it just started running rough lately. The first time I replaced them, the misfire was gone and the car performed. ) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more. 5L HO and recently I have gotten a code for Cylinder 5 misfire (P0305) and now it is starting to idle kind of rough and even shake or shutter after I come to a stop at an intersection. it seems to be problem with 3. Top 10 Causes of a Rough Idle | JL Motorworks. In cases where this valve is clogged or failing, your vehicle will stall instead of slowing to an idle after the release of the throttle. But acknowledges it is not great. I bought my truck to drive not idle so I am ignoring it. These elbows become oil soaked and collapse, creating a leak. The fact that the big gains occur in the lower rpm range is especially important for an AOD car as the 20 or so lbs. Hi, I purchased a 2008 Volkswagen GTI 2. The one problem I am still having is that the idle still sometimes drops when I am sitting still. Alloytec Misfire- Mechanic and Autoelec MUST read. This is a lot of forgiveness in an inspection program. Car has a rough idle. and when i am driving in an 80km zone (35mph) whenever i put my foot on the gas to. I have a CRX with a B16a 1st Gen OBD0. Diagnosing the cause of the misfire (rough idle) on a 2. ( and has stalled a couple of times ). But acknowledges it is not great. My car (94 E320-115K miles) developed a low rpm misfire. The special warranty coverage for this will only cover it if it pulls the right misfire code. Upto 2500 RPM it is very silent and the feel is very smooth. Sometimes the engine will misfire on Idle also, and your engine sensors will get faulty values, and the air-fuel mixture will get messed up. - Warm or cold, the X5 starts smooth but eventually begins to run very rough - Tried disconnecting the MAF but it only makes the engine run worse - If you depress the gas pedel to say 2000 RPM, the RPM will drop to ~1000 then back to 2000 then back to ~1000. If you rev it to 1000 rpm it doesnt misfire or stumble. Slight bogging when accelerating moderate to high. Module Woes. My car: 2011 GT Premium -3. Any ideas?. As everything in my life my car broke down in a super complicated way and no repair shop can diagnose my problem. - - 1966 mustang v8 rough idle / misfire (https: I recently rebuilt the engine of a 66 mustang v8. Felt like a misfire, so I replaced plugs and wires. low and rough idle and stalling at complete stops. My dealer tells me it is normal for ten speeds to act this way. This problem has been getting worse over the last 2 years. When it reached 1500 RPM it runs smooth and when I stopped on the stop light it idles rough. The issue was still there with idle dropping a little low after giving it gas and just a rough in general. What does this code mean anyway? The definition for this this P0171 code is Fuel Trim System Lean (Bank 1). Cracked hoses and other of the type vacuum leaks tend to cause a rough idle. It feels like shaking and sputtering. 141,285 I have a Buick Lesabre 2000 it idles rough and it runs rough while you're driving it what do you think the problem. some say TFI but the car starts right up and idles u can drive it but it misfires under load and at idle , idles rough , i swapped out distributor and tfi no difference, played with timing no change. But im wonder who has it, or who did what to fix it, im thinking seafoam and new plugs might do the trick. so here's a list of what its not:. I can hold the throttle at 3500 and this thing would spit and sputter at me sounding like a dog sh**ing razor blades. when i put in drive (c4) it dies. See Photo 1. com Low RPM Misfire - P0300 or P0308 Codes? rough idle all the time whether cold. Your problem is a misfire. Engines should run smooth and evenly when at idle, never fluctuating in rpm or dying. No, if you up the idle manually, the ECU will eventually reset itself and bring your idle back down to being too low. Replaced wires, cap, rotor, plugs, coil, and TFI control module. MIL returned with same codes: rich bank 1, misfire in #6 and #3. The RPMS bounce around a lot when in Drive (in N or P it idles smoother with the higher RPMS). Rough/shaky idle fix? Fixed stalling, missing, rough idle, surprise result. I have just recently noticed a slight hesitation or misfire from the engine while the car is in drive and the brakes are on. p0300 rough idle and miss at low rpm. By definition, as diesels are compression/ignition, they cannot misfire. The misfire occurs during idle and low to medium rpm load, but not during WOT. idled back to ramp at 800 rpm, wouldn't start the next day. It also idles rough aftter getting off of the hiway and having to sit a a red light. P0316 Engine Misfire at Startup OBD-II Trouble Code Technical Description. Rough idle and light backfire. Some customers may complain of a MIL and/ or engine misfire, rough idle, extended crank, or crank no start in some cases, the misfire may be more apparent on a cold start and may run rough for up to 5 minutes after starting the engine, may count on a single cylinder or several cylinders, and may or may not be felt by the driver. how to adjust idle on 1992 mustang 5. 0 psi; if the vehicle has an adjustable fuel-pressure regulator, set it to 4. One of the most common problems is likely a rough running or poorly idling engine. Step 19 - In some conditions a broken valve spring can effect different aspects of engine performance for example: If just a small part of a coil breaks off, the spring can still close the valve but only at low RPM's, causing a high RPM misfire. Ok here it is: I have a 2005 rs. The feeling is vey similar to the sensation of a tire out of balance. I have a mild E-303, ported TFS heads, Holley intake and a 70 mm throttle body. So here it is in full glory my car with its weird issues. 2005 V6 Mustang. I "power tune"ed the carb, replaced the plugs, and revamped the dash ignition wiring. Adjusting the idle speed or mixture will sometimes straighten out a rough idle. While there are a variety of reasons your Ford Mustang has a rough idle, the most common 3 are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil. High idle, misfire, check engine light, High idle, misfire, check engine light, And yes, it can make the engine idle at high RPM. 3 vortec is idling rough and jerking until I get it up to speed, low compression, I changed the plugs and they were dry. 2006 STI rough idle and. P0506 Idle Speed Low Rough Road Data Unusable P1381 Misfire Detected - No EB (T) CM/PCM Serial Data RPM Lower Than Expected P0507 Idle Control System RPM. BMW Misfire Rough Idle and Skip On Cold Start Diagnosis No Faults 3 Series N51 Engine 2002 Mustang GT misfire - Duration:. Goes away completely above about 2200. 1500 revs at idle is way too high! Theres no reason it should be up that high unless thats at cold idle only. This type of low idle problem should involve a air vacuum leak or dirty/bad IAC vavle but if those check out fine then try replacing the spark plug wires. Rough/shaky idle fix? Fixed stalling, missing, rough idle, surprise result. Misfires can occur at idle, when the engine is pulling hard under load, at high rpm and during throttle transitions as the air/fuel mixture changes. My 1996 Ford Contour did this--I was driving it and the CEL came on, started flashing, and it was idling a little rough. At IDLE, there should not be any more than 5. Thought it was a coil pack, EGR valve. Doug's original 289-2V had received only one valve job in its 42-year history. The first time I replaced them, the misfire was gone and the car performed. Why does my car idle at a really low rpm while stopped and start shaking? My check engine light has been on for like a week now and when i got it checked they said i had random misfires and a misfire on cylinder 3. This morning it started smooth. At first, I replaced the spark plugs with stock ngk ek plugs, it ran ok for a while but after the bike warms up, it starts to misfire again near low rpms. Took the boat out - ran fine for an hour or longer on the way in engine started running really rough at low rpms below 1200rpms Engine runs fine at higher RPMS - Idle is misfiring at low RPMS, #1 cylinder plug is carboned up others are even and wet. When I accelerate, no matter if I just started the truck or if I have been driving for a while and am leaving a stop light, the truck studders, and then will accelerate dramatically. BMW Misfire Rough Idle and Skip On Cold Start Diagnosis No Faults 3 Series N51 Engine 2002 Mustang GT misfire - Duration:. When a vehicle idles low, the vehicle stalls or shakes excessively when the brakes are activated, and this is an indication of a serious engine problem. This morning it started smooth. It doesn't seem to do it until the bike is warmed up. So here it is in full glory my car with its weird issues. You get it up to about 1k RPM and everything is great. 1) Changing distributor fixed the original rough idle/misfire problems. It was tuned up 2 months ago changed fuel filter and when we took it out a lot of air came out instead of gas. Figured I'd share this since I've seen a good amount of people here complain about a rough idle. After that the car ran rough at idle and would stall occasionally. Anyone have one of these, with a similar problem? Any sugguestions? ratherwhalering: posted 11-09-2001 01:03 PM ET (US). When i start the car ( cold start ) it will idle extremely low and stall if i dont tap the gas to keep the RPM up. I loved the rough idle but I didn't like low rpm roughness when driving through the city. Starting, car starts right up and jumps to 2k rpms or whatever when starting, and when its settling back down sometimes it will just die, otherwise idle will drop extremely low to the point of it not registering on the tach, and then idle back up. In the morning when i first start it, it stumbles and coughs, and hesitates. RPMs will fluctuate quite a bit and then settle down. Random misfire issue. If fuel pressure is low, check the fuel filter for obstruction. Yes the bike hasnt been running that much this year , but has had some long rides, and plenty of full throttle. Update: Not the front o2 sensors. No code was set, but she ran terribly, with no power, major misfires, and an occasional backfire. 73 -pypes pype bombs -13k miles Oil is in good condition. Hey guys i have a 95 tahoe and it just started running rough lately. - - 1966 mustang v8 rough idle / misfire (https: I recently rebuilt the engine of a 66 mustang v8. Be aware I swear twice. And at the exact moment it occurs, the engine makes a terrible farting/roaring sound that is just like diesel truck engine braking. Tracking Misfires. When the engine is cold it idles at 700rpm but after it goes down to 500-550 and thats when for instants it seems like its choking. You need to do a misfire diagnosis and then correct the cause of the misfire. Symptoms Of A Misfire Condition? The basic symptom of a misfire is a light to severe rough idle that's felt when the engine is idling and a light to severe engine miss (hesitation) when the engine is under load (for example: your Ford vehicle moving from a stop). The points system has been replaced with electric ignition and set timing, cleaned up all the vacuum leaks, and replaced the old Autolite 2100 with a new Holley. I can hold the throttle at 3500 and this thing would spit and sputter at me sounding like a dog sh**ing razor blades. - misfire under light load - fine at WOT - sluggish at times, strong at others. But keep in mind, the idle speed should be set in stone – if it is inconsistent or changes at random intervals, you may have a bigger issue on your hands. [2000 Mustang GT] Rough idle with P0443 and other codes I recently bought a 2000 Mustang GT and although its been running, the rpm needle often moves around by a couple hundred rpms while idling, the car shakes more, and the engine begins to sound like it might die. Seeing a very low number there (under 100) is not a great cause for concern, but you will probably notice the engine running rough at times, or perhaps the misfire will get worse with time. I have recently put new ac delco spark plugs, checked for vacumm leaks, plenum gasket is in order, cleaned the throttle body and replaced th. The points system has been replaced with electric ignition and set timing, cleaned up all the vacuum leaks, and replaced the old Autolite 2100 with a new Holley. Ford Mustang GT Check Engine Light After Hesitation or Stalling - 19 reports. I had idle misfire on my '03 DOHC for at least 6 months and no codes, no pending. 8L v6, runs rough especially when warm, doesn't want to idle, low power have to keep rpm's - Ford 2000 Mustang question. It usually causes a rough idle and the check engine light will eventually come on. Originally thought it was a vac issue but i cant seem to find a leak. Doug's original 289-2V had received only one valve job in its 42-year history. I'm in the process of running this in. Once thats set the engine will be running more efficiently and you can turn down your idle speed and adjust the idle mixture screws to obtain a nice smooth low rpm idle. Or, it may start and idle fine but then misfire or hesitate when it comes under load. Q: When I use my car it idles at 700 and then stalls when used for 5 min but there are no check engine lights. In the morning when i first start it, it stumbles and coughs, and hesitates. the check engine stays on and when in park, same problem with the idle bouncing up and down. infinity front and sides,votex rear,st coilovers,eurodyne tapp 1000cc tuned,hks ssq bov, pte 5857 pagparts turbo kit with 38mm tial wastegate. Low rpm miss,jerking, Wtf ?HELP 4. Any mustang guru's have some input? I'm absolutely stumped. It starts fine, although the idle is very rough the truck shakes in idle.