I recently purchased a 2001 s4. When I took it for a test drive it felt good. The only thing wrong was a check engine and air bag light on. I got back to the dealership and they cleared the check engine light and showed me the fault code that said it had to do with the battery.

On my way home from the dealership, I noticed the light turn on once more, and just assumed that it was the battery again. Since then, it has been misfiring in cyclinders 1 and 5 like crazy. When I step on it it gets to about 4500-5500 rpms and starts to vibrate a little bit and i lose power for a second or two. After that it kicks back in. I took it in to get it checked out and they fixed the misfires, told me that cylinder 5 had been sleeved, and that the car was chipped.

The mechanic told me that they can only tune cars to factory settings and that I would have to take it somewhere else to get it tuned appropriately to fix the problem that occurs when I step on it.

I'll be honest, I don't know too much about chipped engines, so any expertise would be appreciated.

 

Hmmm I've had a couple different chipped Audi's (00 A4 1.8T & 02 A6 2.7T) and got them both done at the same Audi specialist shop in Northern California which if you are close I would highly recommend having them check it out. If not, then I'd say try to find a specialist in your area. They're called 2Bennett Audimotive in Davis, CA.

For your issue, you might wanna find out what kind of "chip" you've got and look into the possibility of changing the settings. GOOD LUCK

 

The car came with a packet of paperwork in the back seat that had records of mods and maintenance that had been done to the car. One of the mods was a revo stage II.

 

the misfire issue was solved when hey removed the chip? did they swap out your ecu?

 

No. I took it to the mechanic to get the misfires fixed, which they did fix them. for a day. However, they informed me that the car was chipped and said that it needed to be tuned for the chip in order to fix the high rpm lagging when i open it up, and that they couldnt do it there. the next day it went back to misfiring, only much worse.

Im going to pull fault codes tomorrow and see if its still 1 and 5 that were misfiring. if so, im going to test the coil packs.

 

After I checked everything out, I discovered that the new plugs the mechanic put in was damaged, and they didnt even bother to check the coil boots. They were completely trashed. I guess that's what I get for having faith in audi specialized mechanics..

 

make sure to properly gap the spark plugs. If you have to change your coil packs you may want to do a coil conversion and icm delete. it will delete your icm's and let you use the cheaper and more reliable 2.0t coil packs. costs around the same as a set of brand new beru coil packs and eliminates any misfire issues you might be having due to the factory coils.

Coil Conversion & ICM Delete Kit, 2.7T to 2.0T FSI Coils - 034Motorsport | Performance Parts for Audi, Porsche, and Volkswagen

 

I you are lucky enough to have the bolt in Hitachi coils.......stick with them. These are the most reliable ones Audi has used so far. The ICM's do not go bad that often either.

 

Two days later now, the CEL came back on last night. I am assuming the same problem is going to happen again. Would the engine running rich be a cause for this to keep repeating itself?

Again, sorry for my ignorance. I've done google searches and looked through the forums for similar problems, but I can't quite find the same issues.