My truck is idling really high?

2000 CHEVROLET S-10
225,114 MILES • 4 CYL • 2WD • MANUAL
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BRIANNA ALETA
  • MEMBER
  • 4 POSTS
When I crank it up it idles very high. It will go down a little bit when I first crank it up but when I'm driving it and go to stop and mash the clutch it idles very high again. I know I have a vacuum leak somewhere in the HVAC system when I cut the defrost or feet on you can hear the difference. I also have a black vacuum hose coming off the top of the engine that I have no clue where it goes.
Apr 16, 2023 at 5:09 PM
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STRAILER
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 54,178 POSTS
This sounds like you may have a vacuum leak under the throttle body, or the IAC motor needs to be replaced and the passages serviced (cleaned).

Here is a guide that can help:

https://www.2carpros.com/articles/engine-idles-too-high

And use this guide when the engine is cold only:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Here is the location of the IAC motor so you can swap it out. Check out the images (below). Please let us know what happens.
Image (Click to enlarge)
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Apr 17, 2023 at 12:10 PM
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