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 1990 Olds CC E4MC CCC Carb Idle Issues

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smparr

smparr

Posts : 88
Join date : 2018-12-18
Location : Bremerton, Washington

1990 Olds CC E4MC CCC Carb Idle Issues Empty
PostSubject: 1990 Olds CC E4MC CCC Carb Idle Issues   1990 Olds CC E4MC CCC Carb Idle Issues Icon_minitimeThu Oct 22, 2020 9:23 pm

My '90 Custom Cruiser has a Y code 307 with a Hot Air Choke E4MC CCC Carb and is having Idle Speed issues. The choke/fast idle will kick off when I tap the accelerator after warm up but it will start speeding back up almost immediately until it is back at fast idle. I can feel it idling fast at red lights and it almost feels like a miss while driving. The engine is fully warm and this even occurs when I park after a 20 mile drive to work, kick it down and it goes back up. Sometimes it will idle down on its own as it warms but most times it does what I just described. Are there any CCC Carb experts out there that could give me a few pointers to look for. I'm thinking a vacuum part or leak but I can't seem to find an obvious one.
things that have been replaced: New transmission, new valve cover gaskets, new rad hoses, new coolant, new oil, no service engine lights.

Any help is greatly appreciated. After this weekend I intend to do a line for line vacuum hose verification.

thanks,
Steve
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sdowney717



Posts : 109
Join date : 2017-01-01

1990 Olds CC E4MC CCC Carb Idle Issues Empty
PostSubject: Re: 1990 Olds CC E4MC CCC Carb Idle Issues   1990 Olds CC E4MC CCC Carb Idle Issues Icon_minitimeThu Oct 29, 2020 12:05 am

Put a vacuum gauge on the intake port and see what it reads.
Sounds like a vacuum leak, maybe the intake manifold gasket.

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