Grand AM :: 2000 GT 3.4 Keeps Throwing Code P304 - Cylinder 4 Misfire At Idle
Mar 31, 2012
2000 Grand Am GT with 3.4 and 150,000 miles. Car keeps throwing code P304 - cylinder 4 misfire. The main issue is the light and needing to pass emissions test. It has just recently had new plugs, wires, and injector #4.
The fuel pressure regulator was replaced about 3 years ago because it was leaking fuel, enough to smell while driving the car with windows rolled down. Shortly after the fpr was replaced, the acceleration problem seems to have started, either by coincidence, or improper installation. The light/error has been occurring for quite some time, about the past year or two. About a year ago, the car was also throwing a random misfire code. I am not positive if both codes were being thrown at the same time, and when exactly the P304 started.
The crank (or cam) sensor was replaced and worked with the issue for a short while (removed codes/light for maybe a few months?) Before the sensor was replaced, the car would stumble at very slow speeds, 0-10 mph. Also replaced Idle Air Control valve last year. The car would sometimes surge on semi warm starts (not cold, not 190-200) between 500-1000 rpms. The surge would be worse when I had the blower running or the rear defrost on, down to 200 rpms at times.
Currently, the car runs perfectly fine for me, except when trying to accelerate on highway ramps. Its firing somewhat when you step on the pedal, but lags and takes longer than normal to accelerate up to speed for merging with traffic. Drove the car after new injection and said it runs fine while driving, but the misfire seems to be mostly or only occurring at idle.
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My friend has a 2003 Toyota Echo that is throwing a cylinder misfire code. Original code is P0302 and P0302PD. The car is idling rougher, kind of sounds like "put-put-put". Also, the car has no power at all. He lives on a hill and he can't even pull out of his driveway. Lastly, the smell of the exhaust is gassy.
We have changed out the spark plugs...no change. Next, we bought a new ignition coil for the number two cylinder...no change. So, maybe its the wiring. Put the new coil onto the number 3 cylinder and the number 3 coil onto the 2 cylinder. Low and behold, the misfire code changes to P0303 and P0303PD.
Thinking we might have gotten a dud of a coil, we bought another. Same thing...new coil on 2 code is P0302...new coil on 3, code is P0303. Could we just have gotten two bad coils? Oh, coils were a BWD brand coil and Duralast brand. Should we just go OEM from dealer? OR Denso from Advance Auto?
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I recently bought a 00 Excursion v10 2wd everything looked right no major problems. I noticed it has a rough idle and i thought it could be the EGR i went under the hood and there's no EGR in sight. I plugged the OBD reader to see if it would give any codes since the there was no check engine light on and wanted wanted to make sure it worked, It showed a P0304 code its Cyl4 misfire i checked plugs/coils and i noticed there's a little insert inside Cyl4 plugs hole in the head that it has the plug screwed on. I decided to change all the plugs and the coils and i still have the rough idle and code i can hear a ticking noise around the engine in the passenger side.
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1997 Grand Prix 3.8 N/A 181,000 ... I have been getting a misfire only on cylinder 4 which has become more frequent. It "only" happens after the car has warmed up and I turn it off for a few minutes, for instance going in to pay for gas. When I start, it immediately starts to miss but as soon as I hit the accelerator it evens out and runs great, every time. I replaced plugs and wires two years ago with stock.
Upper and lower intake manifold gaskets were replaced around 110,000. All three coil packs have been replaced with original GM packs. I replaced my EGR valve last year due to the original was sticking. My throttle body was cleaned about four years ago. I've seafoamed through brake booster and the rest in gas tank.
I'm stumped that it corrects itself right away by giving it gas. The SES light always come on but goes off on it's own after a few cycles.
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That Car Grand AM 2000 2.4L SE
The current problem with the car is that it is not accelerating fast, for example i would push the petal to the metal and only go 25 mph and my RPM would be 3000-4000. Initial my brother and cousin though it was the Catalytic converter because it was getting hot but that has recently been change along with the fuel filter and spark plugs. but the catalytic converter is still gets red hot so i forbid myself from driving it till i fix what every causing the slow acceleration and the temperature of the Cata when i took the error code think P0300 random misfire to the local Autozone they printed me a long list of things that could be a issue my question is what is the likely culprit so i can fix those 1st before shelling out cash to rebuild a engine. may just have to get rid of it at that point. so i guess what am asking is a list maybe top 10 so i can fix them one by one as my money comes in.
Before the accelerating issue the car would randomly stop when i slowed down or stooped that when i replace the spark plugs.
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I got a 2002 and its giving ma a po301. I know that means a misfire in cylinder 1. I replaced the Coils, Plugs and wires, and now its still there but the check engine light is flashing. What next?????
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I've recently purchased an 01 accent GS and I've replaced the timing belt, water pump, and spark plugs. Ive also got no cold air, and original struts with 119k on the vehicle. Those are the least of my worries now as my car loves quitting out at idle; and it does not get any better hot or cold. One of the plugs was completely black when it was taken out (not by me: mechanic work) so that's when they mentioned a cylinder misfire. they wanted an additional 100 to figure out what that could be attributed to on top of the 550 for the work mentioned above! I am now next to broke and want to see if I can trouble shoot some of the causes myself. I am thinking Plug wires, crankshaft/camshaft position sensors (if there are 2 dif ones?) MAF sensor, o2 sensor, injectors, and fuel filter. My understanding is that the coil pack controls 2 cylinders at a time and I just have 1 bad cylinder...I need to figure out where to start as I have no codes to work off of. also, I don't know how to assess resistance with an ohm meter.
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Replace coil pack?
Swap fuel injectors and recheck?
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I bought this from my brother in better than mint condition. Always maintained. Its generating a cyl #2 misfire code.
It starts and runs like new when cold, but when it warms up, it idles rough, and generates the code. after 1500 rpm it smooths right out and runs fine.
He had it to the dealer just before I bought it and they told him needed a new engine.
I am thinking bad injector, since what seems to be happening is, when cold it gets more fuel, or when u rev it gets more fuel, but at an idle and warm, it doesn't seem to be getting enough maybe. And I see from the maintenance records, a couple of other injectors have been replaced as well.
I think the dealer got tired of replacing injectors under warranty and tried to milk him for a new engine.
2002 ranger extended cab 2wd, 3 door, 232,000 kms 5 speed 3 liter V6, new glass and clutch..
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2000 Tacoma v6 has has always ran good, but has check engine light code P300 & P306. cly 3 & cly 6 missfire, lean bank 1. Vacuum test showed no problems.
I've changed plugs & wires, switched coils around cleaned mass air flow sensor, checked timing. Ran Seafoam through intake, and gas tank. Check engine light went out for about three miles, then came back on. What else can I do to keep that blinking check engine light off?
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Driving last night and my 08 died after searching I found the ICM fuse was blown. I replaced the fuse and now it has a misfire on cylinder 6. I have changed the coil with no luck. I replaced the plugs and wires about 2 weeks ago and I don't find any problem with the plug or wire. I checked at the coil and there is no spark at all on cylinder 6. I was thinking the ICM is bad but was wanting some opinions.
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2000 4.2....Last year I had to replace the coil pack when it started running rough and had a code for a misfire on cylinder 3. It is doing the exact same thing now, same code, same cylinder. Is there something wrong that is causing this?
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My wife's 03 Passat w/ 1.8t is bucking and lurching throwing a P0301 (Cyl 1 misfire) code. We have about 58k on the engine and had the dealer do the 40k service 2 years ago.
So far I replaced cyl 1 spark plug, swapped and then replace coil pack with new. My choices for parts were limited on a Friday night and these are el cheapo Autozone parts. Still missing and throwing DTC, I don't really have access to Vag-Com anymore (just OBD reader at parts store) and I don't have a Bentley's either (I know there's some eye rolling going on now).
How to troubleshoot the cause so I can make a decision to take to mechanic or do a few more parts swaps between now and Monday. I've got tools and a multi-meter. I used to have Vag-Com but it isn't supported on my new laptop (Vista), I tried the USB extension cord on my desktop but it is hit and miss.
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We have a 1999 Audi A6 Avant (wagon) with about 190,000 miles. Best car we've ever owned, and want to keep her running until the wheels fall off (so to speak). We split our time between sea level and a ski town at 7000' (yes, that may be relevant).
Last spring our Trusty (sea-level) Mechanic repaired the exhaust system; both tailpipes were shot (car sounded like a tank). Rather than replace with Audi parts (was going to be a full exhaust system replacement - $000s) they spliced in some new tailpipe. Car ran quietly after that.
However, immediately thereafter (like, on my drive home from Trusty Mechanic's shop) and ever since the car will occasionally stumble (misfire) and throw a check-engine light. Typical scenario is after having been off the throttle while going downhill and then tipping into the throttle at the bottom of the hill, the car will stumble and on comes the CEL. Stumbling lasts 5-10 seconds then gradually subsides. Light stays on, though. Not 100% reproduceable under those circumstances (but doesn't really happen under other scenarios), but happens often enough to be disconcerting.
We recently decamped from sea level to spend the summer up in the mountains (great bicycling), and while the car misbehaved a couple of times on the way out of town, by the time we got to 5000 ft or so, the CEL was no longer illuminated. The car has not misfired once while at altitude despite plenty of situations that would presumably have triggered the issue, were we at sea level.
Trusty Mechanic has replaced some injectors, some coil packs, and the spark plug cables. No behavior change.
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I have a 2000 Suburban 4wd that has a p0300 code. The misfires are coming mainly from #2 and #7 cylinders. Misfires only occur at idle. over 1500 rpm the misfires disappear. I have put new A/C Iridium plugs in, new wires, and new coil packs on both cylinders but the problem is not any better. All 8 fuel injectors all go to 55 psi when activated and drop to 28 when released. All tests were done with my Snap-On Solus.
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So I just had both cats replaced and now the car is running very rough and trowing out mis-fire codes. What could cause this? Going to disconnect the battery to reset the computer to see if that might work.
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2003, not deleted, everything was stock except for he put a Bully Dog on it with can tunes. Died on him was replaced ICP started up ran horrible was throwing different injector codes, IPR was at 84% at idle, plus had a lot of pressure on degas bottle.
Just finished studding, deleting, oil cooler, ICP, and injectors. She started up fairly easy, only to have the IPR still at 84%, ICP bouncing between 670s to 790s this just after start up from the work. Truck still runs horrible and still throwing #5 injector code also using AE and injector 5 wont Buzz. So, would be safe to say Injector harness and IPR sensor?
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I am having a misfire code on the #1 cylinder. Its not bad but I really want to nip it in the butt before it goes out completely. I was told to try and get some of the older style coilpacks that bolt on and go with them. Can I put them on my 03 passat 1.8t.
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Alright Ive had a misfire on cylinder 1 for far too long. I've replaced all ignition coils and plugs with oem parts. Also replaced fuel pump and filter with oem. As well as 2 injectors. Before I would misfire under load, now I misfire at idle..wiring looks good and not cracked from what I can see. Only codes I reciece are random multiple misfire, misfire cylinder 1. And diverter valve mis function because of my BOV. So what do I do now vortex?
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