High idle which fluctuates up and down?

Tiny
DREWATS
  • MEMBER
  • 1996 PONTIAC BONNEVILLE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 168,000 MILES
When I start my car in the cold weather the vehicle has a high idle which fluctuates up and down sporadically between 1500 rpm and 3000. I replaced the throttle position sensor I was told if you unplug the sensor and the problem stops then the sensor is bad but I replaced it twice and it did it with both new sensor. Also when I leave my driveway which is at on end of the block and I drive to the stop sigh and come to a complete stop, idle drops to just under 1000 and idles fine after
Wednesday, May 26th, 2010 AT 4:12 PM

4 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Clean out the idle air control valve and see what happens.
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Wednesday, May 26th, 2010 AT 4:38 PM
Tiny
DREWATS
  • MEMBER
  • 2 POSTS
I forgot to post that I replaced idle air control valve as well and sprayed down the throttle body best I could but didn't take it off. I was also told my be a vacuum leak I replaced whatever hoses were visible on top of the engine
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Wednesday, May 26th, 2010 AT 8:11 PM
Tiny
OKIE_777
  • MEMBER
  • 3 POSTS
Was your issue resolved, and if so, can you report how?

I’ve been having similar issues. Thanks.

(I’m aware this was 13 years ago but I’m hoping you remember lol)
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Sunday, October 22nd, 2023 AT 8:48 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

Because of the thread's age, I suspect you won't hear from the person that originally posted it. Is your vehicle the same year, make, model, and engine? If so, let me know exactly what is happening and I'll try my best to help.

Take care,

joe
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Sunday, October 22nd, 2023 AT 9:14 PM

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