rleey07

Well I replaced my throttle body with a 70mm edelbrock and added a polised IAC and the idle will not drop below 1k, I have tried backing the cable screw back and adjusting the tps sensor, any ideas??????

88Mustang351W

Are you sure that the gasket sealed properly? I dunno about mustangs but on one of my old hondas the gasket didnt seal properly and the idle was high

rleey07

I made sure I cleaned the egr spacer real good, and I put a brand new gasket on. I dont think that it is leaking but i can pull it all off and check..

Bubba 95SN

Spray some carb cleaner at mating surfaces with nozzle extension. Change in rpm will mean a vacum leak. Reset base idle, relearn ECM to idle.

rleey07

How do reset the base idle? It ran fine before i swapped tb....

rleey07

well I sprayed car cleaner all around the tb where it connects to the egr spacer and the idle never changed, I unplugged the battery for a while and cleaned the iac out real good put it back on then connected the batterey back and it idled good for about 10 min at 650rpm then went back to 1000. When you drive it and push the clutch the rpms stay at 1300-1500 rpms until you come to a complete stop then goes back to 1000 rpm. The car ran perfect until the tb, anyone ever had this happen before??

Daddiofink

Reset base idle. There is a tutorial in this forum somewhere, but I don't have the link for it off hand. Basically:

1. Bring engine to operating temp
2. unplug IAC motor
3. hook up a real tach (dash model isn't accurate)
4. start motor and adjust throttle valve screw to get idle to spec
5. plug IAC back in
6. unplug neg on battery for ten minutes to reset your computer
7. Connect your battery and drive for 10 miles let your computer acclimate.

Or something along those lines.

rleey07

Throttle valve screw would that be the screw that the accel cable goes to??

Bubba 95SN

If you have a/c turn it on for seneral minutes before driving. This goes with reset idle instructions. Speed sensor gives signal for rpm to be up untill stop. Thus that function is normal. What is tps voltage?

Daddiofink

It is likely the only screw on the throttle body. It sets the position of the butterfly valve which is actuated by the accel cable so... yes?