Got my Cayenne 4.5 turbo S a few weeks ago (23k miles) and noticed it idles slightly rough and when given full throttle it seems to take off then get held back, and I hear a funny air type sound around 3000rpm.

I ordered 4 new coils ( hoping 4 were ok) took them out and they all look new, certainly no cracks.

Ordered ELM 327 code reader the other day, on runing a scan I got code P1090 and looking at the fuel trims, one bank is over 100 in the negaitve suggesting one knackered maf. Looking at real time monitoring I only see one maf reading does the ecu add the 2 mafs togather to calculate over all air flow?

I have 2 x recirc dump vlave to fit and 2 new mafs arrived today.

Is the above the right way forward??

cheers

Paul

 

no technical folks on here then??

 

I also tried doing that here. It's no use. You're better off at the Renntech Cayenne forum as there's much more technical info there.

 

Thanks will give them a try.

 

no need, read real codes & post info.
I bet 1 coil went wrong, you have an 8 cilinder not 4

 

I know how many cylinders I have. I bought 4 coils hoping 4 would be ok ( tight jock, not a stupid one). They all look new deffo no cracking anywhere. I unplugged each coil inturn while the engine was running to see if one cylinder reacted differently, they all sounded thet same.

Real codes what do you mean? is P1090 not a real code??

 

All fixed. Going like a dream. Difficult job but well worth doing. Faster smoother and more responsive.