Car: Cayenne Turbo, 2008, 500hp, 120,000 km

Today I was driving on a mix of surface roads (B roads) and freeway, when all of a sudden I experienced a loss of responsiveness and the CEL came on. From that point on, any pressure on the accelerator resulted in a rumbly shaking, like I was driving on rumble strips and the power is simply not there. No change in water temp or oil pressure.
When the car is coasting or idling, it sounds fine and smooth. I drove home slowly an cautiously.

I don't have ready access to a read-out. Any ideas or suggestions what I might be looking at?

 

You have several choices here..

1. Get a code reader and know what system is causing the CEL - and just fix that.
2. Start throwing parts at it based on guesses other people make on the Interwebz.

I can promise you #1 is going to be cheaper than #2.

 

Thank you, I found a reader. The error is P0308 (cylinder 8 misfiring).
We'll start by replacing coil and spark plug and take it from there...

 

Sounds good. If the plugs have > 20,000 miles on them - you might consider doing all of them. If one acts up - they've all been used for the same number of sparks so the others are thinking of doing it too. Worth also looking at the other coils - look for any sign of cracking on the shaft of the coil. Crack = failing soon..

Let us know how it works out!

 

Turns out several coils were cracked and the spark plugs were ready to be swapped, so had it all done at the same time. Running smooth again

 

The issue has returned with a vengeance after new spark plugs and new coils in April and a new Air-Oil Separator and some valve at the end of May (and a cleaning of the IC pipe).
After smoking again under deceleration/acceleration like before, car is now once again shaky and idling rough, not responding to throttle etc.
CEL showed up this morning.
Codes are p0308 and p0332 (Cylinder 8 misfiring and something with the valve lifter.

Going back the mechanic's on Monday. Any thoughts in the meantime?