1998 Series 1 V8i
Ok so I replaced the stepper motor and the engine still races at idle. (bout 1800rpm and drops to 1100 in gear) No vacuum leaks that I can find and the cruise works fine.

Here's the thing with air intake, If I put my hand over the air intake trumpet it is sucking just fine but the motor doesn't die when I block it off, it still races. If I remove the air intake bellows and block the air intake at the throttle body then the motor dies (as I assume it should?).

This would suggest to me air entering somewhere between the throttle body intake and the "official" air intake trumpet wouldn't it? The rubber bellows is fine and there are no check engine lights to suggest a fault with either the MAF or stepper motor.

Any ideas anyone?
PS. there is what looks like a manufatured moulded hole in the MAF section of the solid plastic pipe. Is that an emergency air intake in case the filter gets completely blocked???

Thanks,
Alan

 

First, no that is not an emergency air intake.
Have you cleaned the t/body, when replacing the stepper, did you clean out the mount hole?

 

I did Mike, are you thinking it may not be correctly seated?

 

Reseated the stepper motor and it's still the same.
What if the check engine light is faulty (disconnected by a PO maybe!!!) and the MAF is actually dead. when I disconnect the MAF connector the rev's drop for a split second and then pick right up again does that indicate anything?