Constant high idle

2002 BUICK CENTURY
100,000 MILES • 3.1L • V6 • 2WD • AUTOMATIC
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WILDFORDCHILD
  • MEMBER
  • 5 POSTS
Change TP sensor and IAC valve. No help. Unplugged TP sensor and started engine. Still high idling. Could I have vacuum line issue? Does anyone have a diagram of vacuum line routing available?
May 18, 2022 at 10:49 AM
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JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
Hi,

First, I attached the vacuum schematics below for your review. Take a look through them and let me know if they help. Also, note that the HVAC system uses an engine vacuum to control the mode doors and other air flow components. (Pic 3)

Here is a link that explains how to locate and repair an engine vacuum leak. You may find it helpful.

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

Also, I feel as though I have seen this vehicle before. Did you ask a similar question in the past? If this is the same vehicle, did you check the throttle cable by disconnecting it from the TB?

Let me know.

Take care,

Joe

See pics below.

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May 18, 2022 at 8:44 PM
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