Q7Driver75

Bank 2 on my Q7 V8 4.2 L engine is misfiring. Been told that I need to replace timing chain and cam adjusters. 160,000km on truck, 2007. Any other reasons that could cause this. Dealership quoted $6026 to fix...but only the one bank. Car runs fine while driving, but shakes in idle on occasion which forces engine error. Not buying the full story.

flynavy

get a second opinion from another dealer as that doesn't sound quite right....

cuatrokoop

Oil pressure (a lack of) could cause that, gives a false code.

Q7V8

I replaced the oil separator with a new Audi one about 300$, and my car is running even better, like a new one... My guess was probably too much vacuum in the engine reduced the oil pressure, then both tensioner, and lower grade oil increase the problem. I hope this can help you. I also add Liqui Moly oil additive, a wonderfull product made in germany and oil pressure and tensioner are not making any noise, except 4-5 seconds after cold cold start here in montreal winter and Q7 have now 240,000km

Clues

I recently had a high fuel pressure condition CEL that turned out to be caused by two broken timing chain tensioners. The broken tensioners were still intact but caused a slight misalignment in the operation of the timing chain resulting in issues with the fuel rail. The ECM, in turn, was boosting the fuel pressure to compensate.

I had absolutely no driveability issues with the Q7. The CEL was the only indication that something was wrong.