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cylinder #4 misfire


tjbev21

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ok so about a month ago i threw a cel for a misfire... cleared it and nothing came back so i really didnt think anything of it. now 31 days later i get another cel for a misfire in cylinder 4... cleared the code and now 2 days later still no code??? what should be my first step... spark plugs, injectors, or coil packs?
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if you are unlucky, like me, it will end up being a burn valve...I would suggest swapping your #4 injector with your #2 to see if you get the 0302 code. Then you can at least know if it's the injectors. Changing the plugs are a pain in the ass.
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not to freak you out, but I had simillar symptoms, but with cylinder #2. I changed the injectors, plugs, and had the coils inspected, but everything was fine and I kept getting the 0302 code...which was finally diagosed as burnt valve. (5psi compression in that cylinder)
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2&4 are on the drivers side. #4 is rear injector. I also went for a while without throwing a code. But, it became more consistant and my car was running very rough.
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It's pretty easy to do. Just pull the fuel pump fuse start the car and let it run until it dies. Then crank the engine over a few times to release the pressure in the injector, otherwise you'll get sprayed with gas when you pull the injector out and then disconnect the battery to be safe. I'm sure there is a walkthrough in the forum. I't has a hex type screw so phillips or flat head drivers won't work
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By the way, how many miles do you have on your car? You might just need to run a bottle of lucas injector cleaner during your next fill-up. It actually does a pretty good job.
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Hm, I've been having a misfire issue on my 05 LGT. Engine seems to run okay, full boost (stage 2), a little shaky at idle but not bad at all. Check engine light comes on randomly with codes for cylinders 2 and 4. I've replaced spark plugs twice, swapped coil packs around, checked wiring, checked vacuum lines, etc. Any ideas?
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What engine light came on the dash? My was having rough idle when I first started my car and check light, VDC and cruise control light would be on. My car would shake really bad for about a mile and stop shaking. I took it into dealer and they told me that I had misfire on my #1 plug but they couldnt duplicate the shake. So they just left it alone. It already did this 5 times but there was only 1 time the light stayed on. Other times, the ligh would go off as soon as the car stopped shaking.
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but why would the two fault codes occur at the same exact time together?

 

Sounds like the OCV on the drivers side (#2 & #4 cylinders) could be the problem. It's a pretty easy fix. Other than that, you could have a compression test done to see if you have a burnt valve. That's what happened to my car. I should get it back tomorrow.

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Sounds like the OCV on the drivers side (#2 & #4 cylinders) could be the problem. It's a pretty easy fix. Other than that, you could have a compression test done to see if you have a burnt valve. That's what happened to my car. I should get it back tomorrow.

 

Can you PM me details on the repair?

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^adding to why i think its a injector, just from reading all the misfire threads were everyone replaced the plugs then coils with no result, then finally replaced the injectors and bing problem solved....

 

so i think im going to start backwards and replace the injector first.

 

the last misfire i had was in my acura tl types s... and its was runing rough like the subbie but it was rough consitantly thru the whole rpm band (ended up being a coil pack), so thats why im thinking injector, since the car runs fine as soon as you get moving. i also dont smell any unburnt fuel.

 

is there anyway to test for bad injectors? or should i just bite the bullet and replace cyl. #4?

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  • 3 weeks later...
  • 2 weeks later...
Help!! I'm out in the Chicago area right now on a road trip with my girlfriend and I'm getting the P0304 - cylinder 4 misfire (I checked using the built-in reader). Before I left home the check engine light was on so I brought it into a shop where they spent 5 hours on diagnostics just to tell me I had a dirty injector. They said the mechanic cleaned off the dirt and reset the code and that it was fixed. I wasn't fully convinced they had solved the problem but I left on my trip anyways. About 200 miles into it, the check engine light came on again and I pulled to same code but there was no difference in performance so I put a bottle of Lucas upper cylinder lubricant (http://www.lucasoil.com/products/display_products.sd?iid=26&catid=8&loc=show) and kept on driving. Now I'm at my cousins place in Naperville, IL and the car is stuttering badly on 1st gear, the clutch is making a weird noise whenever it is depressed, the idle is rough and I dont even feel safe to drive it. I'm getting the car towed to a shop soon but I was wondering if anyone could give me advice on what to do? I'm not mechanically inclined but I would appreciate any help to get me to complete my trip. HELP!!
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Great news, they fixed my cylinder #4 misfire, apparently it was a bad coil pack. However, the mechanic that fixed it also told me that my clutch was on its way out. I arranged for Genesis Performance in Illinois to install a new ACT clutch and flywheel for me but on inspection they discovered that my throwout bearing had disintegrated and ruined my transmission as well. Now I'm sitting here waiting for parts to come in to make it back to work asap.

 

I am wondering, what can I do about the shop at home that supposedly did 5 hours of diagnostics to not do anything but waste my time and charge me $300? Can I get my money back?

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I've got the same problem (i.e. P0304 code) on my 05 GT. After doing some searching and doing some research on this site, I've noticed an alarming trend of #4 cylinder coil pack, injector, and OCV failures. Here are my problems. My car idles poorly, not shaking, but poorly. It starts off with a bad stumble, but when it reaches a certain rpm, it starts to run better, not perfect, but better. I've replaced the drivers side OCV, this "seemed" to have made the idle better than it previously was (maybe it was wishful thinking on my part), still threw a P0304 code. I've checked for leaks and can find none. Here is my problem that nobody else has seemed to touch on, it has a lazy start. What I mean by that is, when I start the car, it is not the crisp, on one crank, start, it seems to roll before starting (hope that makes sense). The first shop I took it too said the compression was low in that cylinder, but that was before I replaced the OCV, so, I may have multiple issues going on here. I'm going to replace the #4 coil pack next, and then the injector, but, after that, I'm out of ideas. Any other advice out there from the esteemed panel of experts (no kidding, you guys are a lot of help). Thanks.
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