I've noticed that in the colder weather my car is having trouble idling properly. I have TBI, btw. Sometimes in the morning when I crank it up, the engine idles at around 1500 rpm and everything is smooth and fine. Then for some unknown reason, I will crank it up in the morning and it will only idle around 1100 rpm, and the car will start shaking even though the rpm stay the same at 1100 rpm. Generally after the car has warmed up, I can crank it up later and it will idle just fine even well under 1000 rpm. What could be causing this? Cold weather only? Am I worrying about nothing? Thanks for any help.

Josh

 

Red,

What year/engine do you have? The sensors used to control the engine are different in different years, so a little more data would be helpful.

I would suspect that ambient temperature does have some bearing on the problem, though. We just need to find out how.

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Later,
Vader
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"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

 

I have a TBI car, and the two things that come to mind would be possibly the IAC motor or the coolant temperature sensor in the intake manifold. The IAC could be going bad or sticking sometimes. If the coolant temp sensor isn't working, your ecm won't be able to determine when to be in open or closed loop operation. It should be in open loop until your engine warms up. Mine usually idles at 1500 when it's dead cold, and goes down gradually as it warms up.



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

Thanks for the replies. I have a 91 305 TBI if that's of any help.