Back on the road.

[hbhp5]

91  4.0 

 

  Recently replaced head gasket.  New coil, plugs.  Upgrade intake, riser, tuned header.  Air control valve, Throttle control, fuel pressure regulator..     

 

   Now idles at 1200, hard start, stumbles after warm start. 

 

Any ideas~?

 

 

[Pete M]

have you tested the sensors?  even if new they can be off.  could also be a vacuum leak so be sure to check for that.

[hbhp5]

  Will do.  Have checked for vacuum leaks, none I can locate. 

[zaconrad]

Another thing that you could do if there are no vacuum leaks would be to adjust the idle speed motor. At the front of the throttle body there should be a little motor that pushes on the throttle body linkage. I don't remember the correct way to adjust it but it just screws in and out. Another thing would be to check the TPS and MAP sensors.

[ghetdjc320]

4 hours ago, zaconrad said:

Another thing that you could do if there are no vacuum leaks would be to adjust the idle speed motor. At the front of the throttle body there should be a little motor that pushes on the throttle body linkage. I don't remember the correct way to adjust it but it just screws in and out. Another thing would be to check the TPS and MAP sensors.

If your referring to the idle air control valve, that’s a stepper motor and is not adjustable. It’s simply a way for the ecu to bump up the rpms as needed. No if the iacv is not seated properly or is not closing then that could be an issue. The set screw for the butterfly adjustment should normally never be touched. It does set minimum idle though.