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92 S-10 Blazer high idle


who_is_this43
10-27-2005, 02:02 AM
I have a 92 Blazer that's been a bit of a problem, what a surrise huh. I have replaced the EGR, injectors, Throttle position sensor, Air intake sensor and the O2 sensor (3 times in 6 months) due to various problems. Now the engine idles at 1800 RPMs but loads to about 1200 in drive and no service light comes on. I've plugged all the vaccuum lines one at a time from the intake but no help. What has me puzzled is that is idles normally for short periods of time and then goes back to high idle. Any clues on what this problem might be?

Gabe25
10-27-2005, 12:20 PM
I have a 92 Blazer that's been a bit of a problem, what a surrise huh. I have replaced the EGR, injectors, Throttle position sensor, Air intake sensor and the O2 sensor (3 times in 6 months) due to various problems. Now the engine idles at 1800 RPMs but loads to about 1200 in drive and no service light comes on. I've plugged all the vaccuum lines one at a time from the intake but no help. What has me puzzled is that is idles normally for short periods of time and then goes back to high idle. Any clues on what this problem might be?

Did you check your PCV Valve. Make sure that its working. Next try take a look at your timing. Your timing should be at Zero degress. Also try resetting your CMU.

who_is_this43
10-27-2005, 07:23 PM
OK thanks for the pointers and I already replaced the PVC, forgot to list that. Thanks

jsgold
10-27-2005, 07:34 PM
I do not see where you mentioned the idle air control. Did you remove it and clean both it and the area it was in? Can stick and cause high idle. Remove it and clean it, and also measure the length to be sure it is not too short.(do NOT squeeze it) I think the total length should be 1-1/8". Be sure to unhook the battery when removing it and let it idle a while when you install it to let it learn idle again.

Rmbodie
10-28-2005, 04:33 AM
I had this similair problem with the IAC solenoid . Good Luck . Mine acted erratic , idled up and down. run lean , hot . And no idle at all . I installed a new one following all the instructions, Same thing. I unpluged it and screwed the tip (trial and error) until I found the correct idle and drove it away. Now running with a HP carb setup. Rob

ErikN
11-01-2005, 11:03 PM
My 94 had this problem, and it deteriorated to where it started a high pitched whining sound when not under load. Very strange.

Turned out it was the throttle body gasket leaking, which leaned-out the mixture (I think) causing the high idle. The whistle (it was ear-splitting) was the middle plastic part of the gasket vibrating in the gap like crazy.

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