So literally 2 months ago I replaced all the plugs and the coils, and probably ran up less than 800 km since the "operation" and only used the highest grade 94 octane premium fuel.

As it turns out under full throttle I'm getting a misfire in cylinder 4.

Is it possible that I got a bad plug or coil, I replaced them with new OEM's for both?

Has any one had these (or one) go so quick?
Sounds a little absurd to me. Could it be something else?

 

Problem is going to be either fuel or spark related. To check for spark if you isolated it to one cylinder you can swap coils and plugs with another cylinder and see if the problem moves. Swapping coils and plugs on this car sucks though. If the misfire does not move then you may have to check the fuel injector. The other thing you might try would be to run some fuel injector cleaner or Seafoam thru the car to clean up a stuck/dirty injector. I might actually try that first since it would be easier, even though it might not work.

 

Hmmm, yeah, may be cheaper to just replace the plug and coil as opposed to swap around and have to open her up twice. Damn these turbo's for been such a pain to get at the plugs.

But for sure - great idea re the injector cleaner. Will definitely try that first. But like you said, I don't put much weight in that working either.

 

Did you get a CEL? Did you read via Durametric or take it in to the dealer? Any symptoms when you drive?

 

Did you check the gaps?... Obviously they should have been right but I never assume. Very possible you got a faulty coil as well. I've put in brand new ones out of the box that were bad. The Cayenne's had a pretty big run of horrible coils for awhile. At least it's not a 'random mulitple misfire' code, those can be a real headache!

 

Haven't picked it up from the dealer yet - this is what the dealer tells me. Was in for another issue (actuator's in the VTG's needed to be replaced). Now everything is working great except when the car is under full load it seems like fuel is being cut, reading out the faults I was told it was a misfire in cylinder 4.

 

Sounds like a Bad Coil. It Now comes down to replace 1 or ALL 6? It will be a PITA if another coil goes bad a few months later.

 

Right...but he just replaced all 6 two months ago.

 

Just replace the bad one. I went through a similar case myself. Every time you replace a coil you are flipping a coin on whether it will be OK or not. Replacing all six is like asking for a full draw in Poker...