1990 Chevy G20 5.7 High Idle Concern

JOELIO912 · 03-27-2007, 08:51 AM

Vehicle has a high idle at cold start it idles around 800 rpms and as it warms goes to 1200. Already replaced has been, IAc valve, TPS sensor, Fuel Pressure regulator, MAP sensor, and PCV valve, O2 sensor. Reeling at this point wondering if anyone has seen problems with a torque convertor causing a high idle concern . HELP

blazes9395 · 03-27-2007, 12:03 PM

How is the throttle body, if you snap the throttle, does it close properly?, when its running try turning the butterfly closed as much as possible does that help? If it does, get some cleaner and clean the butterfly and the throttle body in general. Also when you installed the TPS did you make sure it is installed correctly, at the right voltage when idleing. How about the IAC, did you make sure the bore was clean before putting in a new one. You could have carbon stuck in there causing it not to work properly. Lastly, you could have a ECm problem, you can'y rule that out either.

JOELIO912 · 03-27-2007, 02:40 PM

Cleaned Throttle Body Thoroughly And Checked For Sticking Throttle Plate. No Luck, Iac Passsage Way Clean As Well. Still Have A High Idle

DFBonnett · 03-27-2007, 04:16 PM

How does it run otherwise? Any hesitation when accelerating? I'm thinking about a vacuum leak.

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