jrmcm

I'm gonna cross post this message in the B6 S4 forum as well...
I'm having a very noticeable rapid vibration when under engine power. This occurs while moving or stopped, in gear or not (B6 S4). It's felt everywhere in the car (seat of the pants, shift lever, steering wheel). When under power while moving I can feel it, dropping it out of gear (and thus to idle) makes it completely go away, or I can feel it while sitting stationary and revving the engine. I'm also noticing a change in exhaust sound (aftermarket, Borla). Any thoughts on this?

mishar

Sounds like misfiring.

jrmcm

If that were the case, I would think it would vibrate at idle as well. Yet it doesn't.

2005AUDIS4

also, i'm pretty sure that you would get the check engine light if it were misfiring. any lights or codes to speak of?

mishar

Not necessarily. Bed spark plug can still manage to fire on idle and loose it under load. I believe it won’t trigger any warning.

AusA8

Was there any resolution to this issue?

I think I may have the same issue...

doylfish

probably coil packs or plugs..i got horrible vibration under power and a CEL when my coilpacks went