Silverado :: 2003 - Intermittent CEL Code P0304 / Misfire On Cylinder 4
Aug 6, 2011
My 2003 Silverado 5.3 has an intermittent CEL. I plugged in the reader and found code P0304, misfire #4 cylinder. I changed the coil, swapped the spark plug and wire from #2 cylinder to see if the code would follow. Nope, didn't follow. I swapped the injector also, same results. My daughter decided to borrow the truck and drove it so low on fuel that the low fuel light came on in the drive way. I added about 4 gallons of fuel and now the light went off. I started the engine after a jump start, and the engine really runs rough and now won't stay running. I am thinking that the fuel filter is probably needing changed because of how low the fuel.
I haven't checked the fuel pressure yet and will do that today. Now, what really puzzles me is the intermittent part. Sometimes it will run with no problem, but then the CEL will come on and the fun begins. The Chevrolet dealer says it's caused by the valves turning in the head and when it reaches a certain spot, it detects the misfiring #4 cylinder resulting in the CEL. If I pull in the driveway with the engine missing, go back out in a short time, start the engine and it runs fine. Same thing if it's running fine and I can start it and the CEL blinks and it begins missing, but may stop and run fine. I am stumped and not so sure about the turning valves.
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Have '01 SE. yesterday I got a misfire in cylinder 4 (code P0304) the service light blinked on and off 3 to 4 times than stayed solid. changed plugs and boots about 1 to 2 months ago, didn't change coils and they r not in the best shape but didn't have money to replace at time. So I replaced the coil for #4 and it still runs rough with code, plug has some ware but looks fine.
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I left my chevy s-10 truck sitting over the christmas (23/24/25) and it was really cold outside and when i got back i started getting a P0304 (Cylinder 4 Misfire). I replaced the spark plugs and spark plug wires. May be the cold would cause this to happen? I think I've noticed the trucks fuels efficiency drop over the past month). May be the fuel injector(s)? Is the s-10 TBI or does it have fuel injectors for each cylinder?
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2000 Jetta GL 2.0 AEG. I am receiving the P0304 which I have identified as Cylinder misfire #4. I read on some previous posts that I cannot be the distributor because if it was I would be receiving misfires on two cylinders. The spark plugs are OEM NGK and have been replaced recently.
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Well, I have a big problem on prius 3, the problem is that it has a big and I mean a big body shake when I decelerate above 30 mph or slowly accelerate above 30 to 50-70 mph, when I fully accelerate, the body shake disappears. When the body shake occurs MIL comes blinking and DTC P0304 comes but not always, but the shake is only when the coolant is hot.
On the other hand, if the MIL is not on with the tester it can be seen that the cylinder 4 has misfire margin, only cylinder 4, every time. Now what I have done is to exchange the injectors, problem remains on cyl4.
-replaced the coils, problem remains on cyl4,
-clean the EGR, problem remains on cyl4,
-opened the engine to see the valves, cylinders, pistons, exchanged the ring set,problem remains on cyl 4,
Replaced the wheels, the problem is still there, now I want to replace the drive shafts.
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I know I can fix this problem, but my question is which cylinder is #4? I don't see it marked on the engine. The counter guys at both my local parts supply stores (whose initials are A and O) can't even look it up for me. If #4 is on the front of the engine, then it's an easy fix. If it's on the backside, then the intake manifold has to come off to get to the plugs and coil packs. It's a bit more labor. I can do it, but I'd rather not have to.
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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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2006 PT Cruiser Touring Ed. The engine light came on 2 days ago, had it looked at today and the error code p0304 "cylinder number four misfire" was diagnosed. What causes that and what would need to be done to fix that problem?
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1997 Ford Mustang 4.6L EFI engine with 67K miles. The engine is actually now in a Factory Five Roadster. It sat on a stand for 5 years but runs well now with the exception of the code. I keep getting a code P0304 (cylinder 4 misfire) and I've checked the plug - the code seems accurate; it is misfiring.
Things I've tried:
1)swapped plugs,
2)this is a dual coil engine so I've swapped coils,
3)the #4 plug is the longest sparkplug wire so I've gotten high-performance wires,
4)heavily grounded the AL head,
5)put dielectric grease on the plug,
Still, ONLY cylinder 4 gives the misfire.
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(This is a continuation of a previous thread: [URL] ..... )
I have a 2005 Nissan Sentra with 75,000 miles on it. Several months ago (see above link) the check engine light came on with a P0304 cylinder 4 misfire code. The only symptom appears to be a rough idle/shaking every 3rd or 4th start for the first 10-15 seconds, but runs smoothly afterwards. My mechanic replaced all my spark plugs (I had new plugs put it at 50,000 miles for the same issue) of which the one from cylinder 4 was worn down much more than the rest. The problem persisted so they replaced my fuel pump and fuel filter and switched the spark coils from cylinder 4 to a different cylinder, but the code still read cylinder 4 so it wasn't the coil. That was back in October.
I took my car back in last week for the same problem and without starting my car (because the problem is worst on the first start) they pushed my car into the bay and did a smoke test, no leaks in the fuel lines. Then they checked the cylinder and said that there was "excess" fuel in the cylinder and replaced the fuel injector. Then after ~3 days the check engine came back on with the same P0304 misfire code. Previous repairs/diagnostics rule out spark plugs, coils, fuel pressure, and injectors.
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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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6.0 .... Have a code Po3o4 Cyl 4 misfire. I pulled the valve cover to remove the injector and found the right half of the rocker mount and rocker arm laying in the head. What may have happened?
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So, my 2003 F150 4.6 that I just put back on the road after a four month break is running like crap. I took it off the road for the winter because it was missing (no codes) and didn't feel like dealing with it then but after running it for a day the CEL comes on. It shows the following:
P0304 - hoping it is a coil pack
P0456 - pending. Gas cap?
P0171 - pending. One bank too lean?
Does the 171 code possibly have to do with the misfire in Cylinder 4? I know it is impossible to tell yet but am hoping there is a potential connection.
Before I parked it in January, it was running a bit rough and stumbled on acceleration but never would show a code. Now all this. Going to change the coil first, tighten the gas cap, check for leaks and see what happens but is there anything common on these trucks that I should also be looking at?
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So I have A 2000 Chevy and i keep getting a code saying i have a misfire on cylinder 8. i have replaced the spark plug, i have replaced the coil. this code is still showing up. what else could this be?
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I posted this problem several months ago about a p301 code that my 2007 Prius has been generating. I eliminated all the easy stuff... plug, spark unit, fuel injector. Over the past year since I've had the car, the CEL light has gone on for a couple months then shut itself off for a couple, then back on ... probably has shut itself off 3 times in the past year, each time staying off about a month or two before coming back on. Some background on the car, supposedly the PO hit a rock and damaged the motor about 2 years ago and had the short block replaced.
Anyway, the CEL has been on again for about a month, and I got a notice for Illinois emission testing, so I decided to take it in to the dealer and have him do a diagnostic so I can get the emissions passed. After an hour and a half of testing they told me that the best they could ascertain, the car has been submerged in water, as there is a lot of rust in areas that never get any rust, and they think there's a short somewhere.
The service manager at the dealership said if it was his car he wouldn't spend the money for another 5 hours of trouble shooting, and if the car runs good he'd just drive it as is. They cleared the CEL and the service manager just charged me for an oil change as they caught a recall on the steering that hadn't been done and figured he'd let me slide on the hundred for the diagnostic.
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I'm having an issue with my 2003 Silverado, current engine is LS1 from a WS6 Trans Am, mostly stock, stainless headers, no cats, stall converter. I replaced fuel pump a few weeks ago and last week i took a road trip and when I hit the interstate the CEL started flashing. I pulled over and used my scanner and saw that it was P0307. I cleared code and continued on. The only noticeable problem was that it was not shifting into overdrive. After a while the light quit flashing and eventually it shifted into OD.
This happened several more times on a 750 mile trip. I had a mechanic friend check it over and he couldn't find anything, wasn't throwing codes at that time. He check sparked plug, swapped the coil to #5 and still had the issue. Didn't get a chance to check the fuel injector. The trip home it did the same thing. IF it were indeed a bad injector, wouldn't the problem be ongoing instead of coming and going? Took to local chevy dealer thinking they could diagnose it but since it didn't throw a code they couldn't find anything.
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We just bought a 2002 Camry with 72,000 miles 2 months ago. It now has 74,000 and while on vacation the CEL came on. I took it to a mechanic who got the code P-0304 off the computer. He swapped the number 4 ign. coil pack with the number 3 cylinder. The CEL light went off and I was able to drive the 300 miles home. The next day the CEL started again, but this time it's flashing. I changed the spark plug, it looked good, and still have the CEL on with the P-0304 code.
I've inspected the wiring to the number 4 ign. coil pack and it looks good. I'm thinking the next thing would be the fuel injector.
The car runs great, you'd never know by driving it that there is a misfire occurring. If it's not the wiring or fuel injector what should I check for next?
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2008 Ranger 3.0L. I am trying to figure my next step in diagnosing a #4 misfire. At regular speeds I really dont hear it or feel it, mostly at idle warm or cold. 3.0L with 275,000 kilometers on it , reg oil changes.The CEL is on, but not blinking. Pulled a p0304 code. I then changed out the bosch plugs I had in with ford plugs and wires. The #4 plug looked okay just bigger gap. Still got the code.
I hooked up a sparkplug light to the coilpack and did not see any missing flashes . Changed fuel filter, checked fuel pressure,all within specs. Changed the oil and did not see anything in it. I read that it could be an injector but I have to remove the intake manifold to get at it. I also read to check compression. I figured if I have to take off the manifold I would put a new injector in, instead of switching them around. What is the most common cause for this code?
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2002 Montana code P0304 light was flashing now solid, swapped coils no change, new plug and wire no change, found air box plugged solid from hibernating mice cleaned out thats when light went from flashing to solid still misefire. I've been told its the injector.
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We recently bought a used 2005 Camry LE 4cyl 2.4L. When we test drove it there were hardly any symptoms and no CEL. After driving it for a week we start feeling a stuttering every once in a while, no CEL still so I thought it might just need a tune up.
Replaced the plugs (which were in bad shape, were Iridiums, friend mentioned it seemed like they were burnt, white blistering like high RPM burn) with new NGK Platinums and replaced the air filter (was also in bad shape, was K&N that was badly clogged up and black).
Drove it around, let it idle, turn on AC, no problem not a hiccup. Next day arrives and the car is misfiring worse than before. CEL comes on too. We get the codes and its the P0304 I mention in the title.
We check the coils and the plugs and they fire, we switch coil 4 and 1 and clear the CEL, then later the CEL comes back on and it's still P0304 so we rule out the coils. The plugs come pre-gapped also.
The misfires are at their worst when idling and trying to accelerate hard, I can hold it at 2000-3000 RPMs with no hiccups or very few ones. Misfires worse with AC on.
Only thing left to do is check compression, try to clean the injector with fuel additive and premium gasoline, or replace the injector, at least that's what I think.
It has 86000 miles.
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Went on a trip Sunday, and i saw my engine light come on after i put gas in the car. I pulled over, re-checked the gas cap, and it was fine. Car felt fine.
When i got home, i used my OBD2 scanner, and got the error P0304 Code - Cylinder #4 Misfire. I cleared the error and drove the car some more, no issues.
Yesterday, my wife took the car and she said it was hesitating and sputtering, but the light hasn't come back. I have an appointment at the dealer tomorrow, the car has under 80,000k, so the warranty should kick in.
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