Erratic idle

1988 DODGE RAM
117,000 MILES • 5.2L • V8 • 4WD • MANUAL
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HAL STEWART
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  • 1 POST
When I start the truck it immediately revs up (no tachometer) to sounding relatively high but then comes back down to a normal idle, temporarily. As the truck then continues to idle, the engine slowly slightly goes up and down, up and down, etc. The maintenance required light recently turned on also.
Dec 3, 2020 at 11:45 AM
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ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Good afternoon,

There is a idle control motor that causes this issue. The gears inside strip out and the motor does not stay stable. The idle will go up and down.

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

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

I attached a picture for you of the part on the throttle body.

Roy
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Dec 3, 2020 at 12:33 PM