every time I start the car the rpm shoots up to 4000 for a few seconds and then comes back to normal the idle seems to be low as well (450) icarsoft code reader is saying miss fire on all cylinders
any help or pointers would be much appreciated ( 4.2 supercharged 2006 )
thanks
dave

Possible air leak after Maf .
I dont know for sure but had a car once that if you started it with a sensor out of the inlet it would rev hard on its own.
Was not the sensor it was the fact air rushed in.