2000 Blazer Idle is Too High Then Goes Down

2000 Chevy blazer (s-10) 4 by 4. Engine Size : 4.3 Vortec.
I have an idle problem. When I first start the car, the idle only goes to 800 rpm. After it warms up, as I am driving and approaching a stop, the car idles at 1100rpm. After coming to a complete stop, it stays there for two to three seconds, then goes to 600rpm.


Things I've done: idle control motor; throttle body cleaning of carbon; and a complete tune-up and the TPS sensor all done in the last 6 months need help thanks.

 

Is the check engine light on, and are there any known trouble codes from a computer scan?

Hi. Thanks for getting back to me . there are no codes and no check engine lights on they scanned it and nothing.

 

Answer: Well, with no codes to go by, and the things you have already replaced, it sounds like a problem with the Idle Air Control motor (IAC). As is says, this controls the engine idle. Throttle cleaning usually helps clean the valve, but if it is failing electrically, then it won't help. Also, after a throttle clean, the idle may need to be relearned. Disconnect the battery for a few minutes, then start the Blazer with the air conditioning off, and let it idle and warm up for a least 10 minutes. Then shut the truck off for a minute or two, then start and let it idle for 1 minute, then take it for a drive. If that does not help, the IAC may be faulty. It is located on the drivers side of the throttle body, near the TPS sensor.

 


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  • Guest - Know more

    Since this person stated they changed the IAC, probably NOT the problem. Mass air flow sensor will cause this issue as well. 96 Silverado DIY.