Misfire problems

**PAimolaS4** · 05-05-2008 09:39 AM

Hey everyone just wondering if anyone had idea ideas.....When I give it some gas the car tends to studder around 3-4,000 rpm then kicks back in. The CEL light will blink and turn off. So far I have replaced the spark plugs and put a new MAF in and also changed 2 of the 3 coils. When i pull the codes it gives me misfire in 1,4,6. So i replaced 4,6 to my suprise they came back when i pulled the codes again. Any help/idea would be appreciated.

Thanks, mike

**The_Jerbel** · 05-05-2008 12:30 PM

Did you test your ICM's?

**AudiSportB5S4** · 05-05-2008 12:56 PM

there's roughly 1 million things to cause the misfiring. If i were you search under "misfires" or "misfiring" and have your pick! Pretty much a good start is a boost leak test, sounds like thats not your problem. As Jordan said, try to test your ICM's if you cant do that meetup with someone with an S4 and swap with him see if that helps. I had a very annoying misfiring problem a while back and i ended up replacing 6 coilpacks, new plugs, and also a coolant temp sensor.

**RolledMySTi** · 05-05-2008 01:40 PM

Have you pressure tested?

**PAimolaS4** · 05-05-2008 03:17 PM

No pressure test yet, the next thing I was gonna check was the ICM which coincidentally a friend mentioned to me lastnite, seems like a common problem that throws these kind of codes...Thanks for all the help!

**RolledMySTi** · 05-05-2008 04:38 PM

I would pressure test asap. I know when I had misfires it was a boost leak. Damn cheap tbb.

**The_Jerbel** · 05-05-2008 06:08 PM

Yeah, there are a million and one causes for misfires. The best idea to to eliminate all the free solutions first.

Pressure testing, as well as testing the ICM's, swapping the coil packs, changing spark plugs....these are some of the first things I check for when dealing with misfires.

**kontener** · 05-07-2008 10:03 AM

Speaking of misfires. My car (2001 s4 with 80k) has been always misfiring as far as I can remember. I detected it first when I chipped it via GIAC, then it continued after I removed the chip. I had the car serviced at dealership for months when it was still under warranty – they did all kinds of things to find out the source of misfires and ended up replacing the entire engine block – go figure.

Then I had no misfires for a while and they came back along with the check ending light. I keep on driving for over year and a half.

Just last week, after filling up a tank at my local gas station (93 octane) my car started ‘acting up’ stuttering, stalling, etc. to the point that I could barely drive it. I had it scanned several times and had misfires on all five cylinders and ended up in the dealership. They had the car diagnosed and after $120 I learned that one the spark plugs had electrode missing!!!

They recommended that all plugs are replaced along with the coil of the bad spark plug. Indeed, when I removed the spark plug the electrode is GONE! How could this have happened? And most importantly where did the missing electrode end up? What’s the likelihood that it’s still in the cylinder? What do you guys recommend that I do?

**ThePaintballGuy** · 05-07-2008 10:19 AM

DANG man, that kind of sounds like my car right now. I have mine in the shop having the head gasket replaced because I was leaking in between the cylinders! It really really sucks. GL with everything and if you can't figure it out do a compression test and PRAY that it passes that, unlike mine. 0 compression in cylinder #3 FTL!

Josh

**The_Jerbel** · 05-07-2008 11:26 AM

Originally Posted by kontener

Speaking of misfires. My car (2001 s4 with 80k) has been always misfiring as far as I can remember. I detected it first when I chipped it via GIAC, then it continued after I removed the chip. I had the car serviced at dealership for months when it was still under warranty – they did all kinds of things to find out the source of misfires and ended up replacing the entire engine block – go figure.

Then I had no misfires for a while and they came back along with the check ending light. I keep on driving for over year and a half.

Just last week, after filling up a tank at my local gas station (93 octane) my car started ‘acting up’ stuttering, stalling, etc. to the point that I could barely drive it. I had it scanned several times and had misfires on all five cylinders and ended up in the dealership. They had the car diagnosed and after $120 I learned that one the spark plugs had electrode missing!!!

They recommended that all plugs are replaced along with the coil of the bad spark plug. Indeed, when I removed the spark plug the electrode is GONE! How could this have happened? And most importantly where did the missing electrode end up? What’s the likelihood that it’s still in the cylinder? What do you guys recommend that I do?

Hopefully it got blown out of an exhaust valve...

**kontener** · 05-08-2008 10:31 PM

A quick update. I picked up 6 SDK spark plugs and replaced them all. When putting the plugs in I noticed that the coil and the port on the second cylinder, on which I had plug with a missing electrode, looked pretty burned. See pics.
I’m not an expert by any means, but do you think a bad coil could have caused uncontrolled electric discharges outside of the cylinder? Just trying to connect it with the fact that the spark plug electrode is missing.