I am in need of assistance, i have a 2007 Audi A4 Quattro. A couple weeks ago my car started to misfire and the check engine light flashed and then stayed on. the misfire will only happen under load, and around 22-24 hundred RPM'S. the car idles, and runs fine as long as i do not accelerate quickly. I had the computer checked it said that it was a misfire in cylinder 3. I had recently had the Coil packs replaced about 6 months ago but i went ahead and replaced the coil pack again. this did not resolve the issue. My car has 97k miles on it. I replaced all the spark plugs next, this did not help. only other thing that i know would cause a misfire is the fuel injector, i just replaced those this weekend. the car still misfires at the same point and im at a loss now. can anyone suggest something that may cause this issue other then the coils, plugs or injectors.

 

Hi,

I'm in a similar situation. I have a 2006 A4 Quattro 2.0T with 195000km and it has a misfire problem.

Like you, I have changed the coilpacks and spark plugs myself. On a hunch I also asked the dealer to replace the HPFP cam follower.

The dealership also changed out the PCV, Intake runner flaps and a HPFP sensor (I believe) for free under a TSB.

Since I kept throwing parts and money at it with no results, I ended up getting a vag-com (should have been the first thing I did, tbh).

The codes I pulled indicated that cylinder 1 was the culprit, but I don't have the check engine light on nor does it come on during misfires. I also have a engine mount code as well, but its probably not related.

Even with the new coilpacks and spark plugs I swapped coils and plugs around and it always comes back to cylinder 1.

I looked around and it seems that people are coming up with all sorts of conclusions for this, from carbon build up to failed diverter valves. Some have even suggested that the engine compression is no longer good. Others have suggested that it could be something as simple as a boost leak.

Personally, what I'm going to do, is do a compression test across the cylinders and also check for boost leaks. You might want to do the same. Since you've already ruled out fuel, and spark (unless you have a broken wire which is intermittent) compression might be something that you want to look at.

 

I have the same car, same year and mine is doing the exact same thing, but instead of cylinder 3, it’s cylinder 2...super annoying, I just want my baby back to normal.