engine idles high

[91sonoma]

A freind has a 1993 with a 350 w/a 4l60e trans. It started to idle high, shift hard and stall sometimes. He chainged the iac, and tps but did not work. I hooked up my scanner and it would not connect. all fuses are good. Any idea's to look for.

 

[Mycotroph]

did you check for vacuum leaks? if the lines are all good try spraying some starter fluid around the tbi if it bogs down the seal is sucking air

 

[Schurkey]

A freind has a 1993 with a 350 w/a 4l60e trans. It started to idle high, shift hard and stall sometimes. He chainged the iac, and tps but did not work. I hooked up my scanner and it would not connect. all fuses are good. Any idea's to look for.

WHAT scan tool did you use? Is is supposed to work with a '93? Have you used it on other OBD-1 vehicles successfully?

 

[Sabinoerc]

A freind has a 1993 with a 350 w/a 4l60e trans. It started to idle high, shift hard and stall sometimes. He chainged the iac, and tps but did not work. I hooked up my scanner and it would not connect. all fuses are good. Any idea's to look for.

Best is to get scanner to work. Without any scan data first thing I’d do is check fuel pressure, check or replace CTS, and clean all the grounds, especially one at CTS as I think it’s ground for PCM

 

[91sonoma]

Checked all fuses then pulled the ecm out and found corrosion on the terminals, cleaned with electrical contact cleaner, Trucks runs great now.

 

[1997]

nice find and posting solution.