ppinto1

2004 A6 2.7T 6 speed: performed timing belt service two weeks ago. Ran fine. Brought car in to dealer to have syncros replaced for 1-4. I had the clutch replaced while the trans was out. In the spirit of good maintenance, I changed the plugs when I brought it home today.

When it was back together, I let it idle for a while and scanned the codes. I had had some random misfires, and I'd hoped the new plugs would clear it up. No misfires were being logged, and I went for a test drive.

Everything was completely normal until about 5 minutes in. I had a dramatic power loss, and the engine began to severely miss under load. It was hard to get the car over 30MPH.

I double-checked everything when I got home. Connections are fine. Engine load in VAGCOM is in the high teens% at idle - which is what it was before (so I think MAF is OK).

I re-installed the old plugs and the problem remained.

I began to pull coil packs off and found that removing 5, 6, and 2 have very little effect. There was also no audible sparking (like on the other plugs).

I replaced my plugs with Champion rc10pyp4. Is it possible these plugs killed my coil packs?

Could the tech have loosly connected a ground when the trans was re-installed? If so, where would it be?

I considered that maybe I had a sprocket a tooth off when I did the timing belt - and that the variable valve timing kicked in during the test drive and I bent a few valves... But, I drove about 200 miles with the new belt and they were all fine. Plus, the engine sounds like the compression is even when its' cranking.

Any ideas would be greatly appreciated. I'm hoping it's the coils. But, even if the plugs were wrong, I don't see how three of them could have failed at once. Has anyone else seen multiple, simultaneous failures? Is there a better test than what I've done?

Thanks,
Peter

quickaudi:STFA

did you use the bar when you did the timing belt?

ppinto1

I called the local VW dealer (no Audi here...) and explained what I said in my post. He said he's seen a lot of coil failure with non OEM plugs, and recommended I change all the coil packs and install the stock NGK's.

I did so, and the car runs great. I didn't think the coil packs were so sensitive. Or, maybe mine were ready to go anyway. I noticed the part number on the replacements is different. The last character changed from "L" to "R" (and I verified it didn't mean left or right...

Peter

quickaudi:STFA

wow, bet that costs a pretty penny

ppinto1

When you consider it's for six coils, it doesn't seem that bad. But, the plugs were still $15 a piece. Germanautoparts.com had the coil packs for $23/ea and the plugs for $11/ea. Too bad you can't plan ahead for this type of thing.

On the positive side, the car never idled so smoothly. And, it might just be my imagination, but the engine seems to be more responsive at lower revs.

Who knows. Maybe one or more of the coils were always flaky.