Mas air flow , tick over issues

Hi Hopefully someone can help Iam trying to get my gto ticking over correctly , the stepper valve has been replaced , with a new one , It ticks over at 1500 , If i rev it , it misses a bit , But if i unplug the mass air flow sensor it ticks over at 900 ? Not a smooth as it should , No missing , It is on axle stands at the moment as i have just put the gear box back in , so i have not tried it under load , Any help would be much appreciated

Many Thanks


What car is it TT NA MK 1 2 3 4

Hi That would help

Mark 1 twin turbo 1991

If I remember correctly the stepper motor/IACV should be “calibrated” so to speak, I’m not 100% sure how to do it but you could lower the idle slightly using the screw on the throttle body, sometimes it’s covered by a cap mine wasn’t.

Maybe it does ? Ever now and again the car will tick over at 900 rpm , for a bit then it's back to 1500 ? ,Some one mentioned the throttle body might need cleaning ,so I will give that a try ?.

Screw adjusted on the throttle body , it needed turning 180 degrees 4 times ? Sorted well happpy