Are all of you guys with coil problems getting your coil packs from Audi dealers? If so, you need to just spend the money and buy the hitachi coil packs from ecs tuning. I had that same issue and decided to buy all new coil packs from ecs tuning. 30k later and still no misfire problems. Dealers might be selling you the old ones. Coil packs are 125 shipped for all 4. Easy as hell to change out. Any noob can take on this task. There is a DIY site that can help if need more info.

 

My car has no acceleration (shakes if you press on the gas), and idles really rough.

I have the Ross Tech VCDS, did a scan and found faults on 3 of 4 cylinders, with the 4th being intermittent. I replaced all four ignition coils and spark plugs, which seemed to fix the problem. The car was purring! Took the car for a road trip, over 1000km, and the week after I come back, the car started having the same problems.

I scanned the car again, and it came up with a fault in cylinder 3. I thought maybe the coil was a dud, so I switched it with coil #2 and did another scan. Sure enough, the fault moved to cylinder 2. I replaced the dud, and car ran smooth again. A week later, the same problem, in the same cylinder. This time I replaced the coil and the plug (in case it was a bad plug) and make it home nicely, but the next morning the car started having a fit again.

Any ideas on what could be causing only coil #3 to fail?

 

I have a 2003 A4 1.8T (purchased used 7 years after the 1st post on this thread) and had the same coil problems described. I am replacing those Bosch coils as they fail with Hitachi coils (same as in the ECS Tuning upgrade keep kits) purchased used from Wolf Auto Parts. My coil related check engine light problems went away.