1999 Chevrolet Monte Carlo idle drops

Tiny
2CP-ARCHIVES
  • MEMBER
  • 1999 CHEVROLET MONTE CARLO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 79,000 MILES
1999 Chevrolet Monte Carlo mileage: 79,000. When the car is cold and I start it the idle goes to 2000 rpm and slowly drops to around 800 rpm then surges back and forth. It also seems to be skipping. If I let it sit for 3 or 4 minutes the service engine soon light comes on, but if I just touch the gas it goes off. I took it to be repaired but they couldn't find any computer codes so they cleaned and rebuilt the throttle body but it didn't help. I brought it back two more times and they replaced the 02 sensor and the EGR valve and the problem is still there. It runs fine once it's warmed up.
Wednesday, February 2nd, 2011 AT 7:14 PM

2 Replies

Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
We suspect a faulty idle speed motor. If not done recently, a major tune up, including plug wires is in order here.
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Wednesday, February 2nd, 2011 AT 7:15 PM
Tiny
DAVE'S BIG BACKYARD!
  • MECHANIC
  • 262 POSTS
It sounds simple, but it sounds like a vacume leak or a weak fuel pump. If you can take the car somewere and have it smoked for vac leaks
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Thursday, February 3rd, 2011 AT 1:42 AM

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