Unfortunately I've neglected changing the spark plugs in a while. I've done so now with NGK iridiums. But still throwing the code. Thought it may be the ignition coil next. Swapped the current coils around to see if the code would change and no such luck. Erase the code and it still comes up as P0304.
View 5 RepliesWe 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?
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.
View 3 RepliesWe 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.
2006 Subaru Forester X 2.5L AT non-turbo
I changed the oil and oil filter; replaced the air filter (Fram), and replaced the alternator and a/c belts. I also got a full tank of gas at Sam's Club, I was nearly empty. I've gotten gas plenty of times there, before.
Next day, the CEL comes on. It's a P0304 code. (Cruise control light is flashing, too.) Engine stumbles and runs rough when cold; idles fine when warm, runs OK, but not the same, when warm. CEL is steady, which is "not bad" but I can make it flash if I hit the accelerator while the engine is cold. Resetting the computer by disconnecting the hot battery terminal didn't work; CEL came on again two days later and symptoms remained.
I buy some MAF cleaner (CRC) and use it; MAF was pretty dirty on the upstream side, actually.
I'm going to change the plugs and wires (they need it, anyway) and I've ordered a new ignition coil, which I'll also switch out.
I've also ordered the gasket for the throttle body, which I'll take apart and clean once that comes in. Last step is to order replacement O2 sensors.
I'm 99% certain there's nothing wrong with the engine, in terms of rings, valves, pistons, etc. I think I'm covering all the bases in addressing this myself. I'm on a limited budget so I'm doing all the labor myself and ordering non-OEM parts on-line, after researching to make sure the parts have a good reputations, fit, etc. (Yes, that's all a big FU to Subaru service for being over-priced but besides being relatively poor I also enjoy doing this stuff.)
2004 Accent - auto. - 100K miles
CEL for code P0304. I thought I had it solved but now it comes on after every fuel fill-up. Its happened at least 5 times or more. I know what the code means (ign. misfire #4 cyl.).
I read and checked what affects the code but this one has me baffled. I thought at first it is the evap. canister but the car takes a fuel fill-up without any trouble and it is not hard to pump it all in and does not give me the code. If I put a bottle of STP gas treatment in the tank it clears the code after about 40 miles driving but it doesn't explain why it sets off the CEL on every fill-up. I also thought I may have sediment in the tank and the fill-up is stirring it up but I have filled her up and various capacities. Also, several weeks ago I got the CEL code P0441 for the purge control valve. I replaced it, cleared the CEL and it never came back on. Fuel filter has never been replaced because it is built into the fuel pump assembly.
Overall drivability and MPG's are not affected.
The code p0304 pop up last week, I have 50800 miles on my car, I unplug the spark plug and the ignition coil from the cylinder 4 and when i start the car I can there is a spark so the wire the spark plug and the ignition coil is good... I changed the fuel injecter with the one from cylinder 3 I cleared the code and it came back?
View 4 RepliesI changed the coil on cylinder 4 on my 2004 V6 Tacoma and the p0304 code keeps coming back along with the hesitation and missing when I accelerate. The wires were replaced a month ago. What now?
View 3 RepliesHave '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.
View 1 RepliesI 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?
View 8 Replies2000 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.
View 2 RepliesSo, over the past day and a half my beloved B6 has been putting me through the wringer... Sunday morning I fire it up, drive to church, turn the car off and everything is fine. Church is over, I drive home, turn the car off and my cooling fan keeps running... I go inside and check again in about 15 minutes hoping it had shut off after 2 minutes or so, but nope, still running. So, in order not to kill my battery, I disconnect it. I let it sit for a few hours and went back out hoping that leaving the battery disconnected would reset something, but as soon as terminal touched the lug, the fan kicked on again.
Now, for the electrical issues that have come with this problem... Whenever I hook the battery back up, a few things can (and usually do) happen. The steering and traction assists don't work, the parking brake malfunctions, the transmission shifts HARD (if feels like somebody is rear-ending me), occasionally the transmission just stays in 3rd gear, and all of the PRNDS emblems in the dash readout are highlighted as if they're all in gear at the same time. Now, cut the car off and back on a few times and most of these issues go away, but other times I've got to fight it a while and disconnect/reconnect the battery for everything to fix itself. I popped my scanner on it, because it's throwing a CEL as well, and aside from the P0304 misfire code (stupid intake valve crud...), I'm occasionally getting P0864 - TCM Communication Circuit Range/Performance. Not sure what's going on, but it seems like my car is self-destructing...
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.
I was on my drive in to work Wednesday and the car once warmed up started surging and cutting out. I got it to work and home again and hooked up my code reader and came up with P0304 meaning misfire in number 4 cylinder.
View 2 RepliesI 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.
View 1 RepliesMy 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.
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?
Back on February 14th ,I had my 2013 elantra gls towed to the service dept for arching and a rough idle. It was a code for #3 cylinder and a cleaning of the coils. Everything was good until again this morning ,only this time the engine light is on with all the same symptoms. There is 14,800 mile on it, I hope they get it right this time because it is a PITA to work this around my schedule at work.
View 7 RepliesI did a valve job on a 2002 Santa re 2.7 after I got it done and all back together I don't have and spark at the coils all of them are dead I'm sure the coils did go bad form sitting.
View 2 Replies1997 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.
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?
View 9 Replies