waiting at a red light the car sort of jumps?

116,000 MILES • 4 CYL • FWD • AUTOMATIC
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VIOLET
  • MEMBER
  • 3 POSTS
I have a 1999 Toyota Camry with 116000 miles. Sometimes when I come to a full stop, or i'm waiting at a red light the car sort of jumps, and then it turns off. Sometimes I feel when its about to turn off,so I put it in park and give it some fuel and it doesn't turn off, but I have to be fast enough. I've changed the cables, spark plugs, and air filter. I change the oil every 3000 miles with full synthetic. I changed the timing belt at 105000 b/c a mechanic told me that this would take care of the problem, but so far no luck. It cannot be diagnosed b/c it does have a light engine on.
Jan 6, 2011 at 7:51 PM
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SQM
  • ✓Experienced Mechanic
  • 6,383 POSTS
Hello,

This sounds like you might have a dirty idle air control valve (IAC).
The IAC controls the engine speed at idle. It is located on the throttle body.
Over time dirt and debris can build up inside the valve and that will restrict air flow. Which can lead to idling issues.
If it is bad enough it will make it difficult to start the engine.

Many times, this can be improved by simply cleaning out the IAC.

Here are a couple of helpful guides:

https://www.2carpros.com/articles/how-a-idle-air-control-valve-works
https://www.2carpros.com/articles/idle-air-control-valve-service

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.
Jan 19, 2022 at 12:29 PM
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