Originally Posted by Hugo
My NA Auto Coupe has started idling at 500 rpm and has a stumble, it occassionally stalls and once restarted is OK for a while.
Throttle response has been slow and it is DEFINATELY low on power.
But the most disturbing part is it has twice now decided to accelarate from rest to 1500RPM the last time sending me into the back of the car in front, minimal damage but a worry.
Now it does have the Powerchip ECU ugrade exhaust cold air and all the rest but the dealer is mystified.
Any thoughts would be appreciated
Try the code scanners, but you're going to probably need a full real-time OBD-II diagnostic while running the car (with something like OBD-Key)
The real important things you have to look at are the Exhaust AFRs and the Fuel Rail Pressure.