I am stopped at a traffic light, or waiting to turn it stalls suddenly

JSBOND

MEMBER
1999 CADILLAC STS
V8
2WD
AUTOMATIC
140,000 MILES

When I first start the car, no matter how cold, I can let it idle in 'park' for an extended period of time and it NEVER dies. The minute I drive it. Be it a short distance (i.E. Just to the post office), if I am stopped at a traffic light, or waiting to turn (in other words, idling "in gear") is when it dies. This happens whether the car has JUST been started, or after I drive it 72 miles to Lewiston and am at a light. Thought it was weird it wouldn't die, sitting in park, in the first place. Just had a tuneup and fuel pump replaced, so not that. When it dies, it dies cold. No chugging or anything. And, so far, will immediately restart without issue or effort. Still, unnerving for this to happen, albeit intermittently (of course), at a busy intersection.

Thanks for anyone's advice.

2 Replies

HMAC300

MECHANIC
48,601 POSTS

Try cleaning throttle plate on both sides and iac hole with choke cleaner they get gummy and do what you have as a problem.

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Saturday, January 17th, 2015 AT 1:10 PM

KEN L

MASTER CERTIFIED MECHANIC
47,256 POSTS

I agree with HMAC300, I would service the throttle body and replace the idle air control valve, here is the location in the images below. Here is two guides you can go over which will help us understand what's going on.

https://www.2carpros.com/articles/stall-at-idle

and

https://www.2carpros.com/articles/throttle-actuator-service

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