Idle issues
Thread Starter
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Joined: Sep 2025
Posts: 9
Likes: 1
Idle issues
Hello, I’ve been having issues with my 1978 corvettes idle. Previously, I would start the car and then the engine would steadily warm up and rpm’s would reach 1400 and stay there. I would tap the gas pedal and the rpm’s would drop to a steady 700-750 ish. It was behaving normally this way in the morning. However, I went to start it later and the rpm’s would start climbing from 500-1000 and then the rpm’s would start bouncing from like 600-900. What could be potential issues? Thanks
Melting Slicks
Joined: Apr 2021
Posts: 2,711
Likes: 2,160
From: Minnesota
Your first specs of 1400/750 is a great high/normal idle. When you go to start it later is it still warm from before? Also what is your ignition timing set to and where is your vacuum advance hooked up?
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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Cruise-In VIII Veteran
Bouncing idle can be caused by a number of factors.
From weak springs in the distributor to vacuum leaks that open up when the engine is hot to any one of a number of carburetor issues.
even issues with vacuum thermo switches, faulty heat risers, etc. etc.
From weak springs in the distributor to vacuum leaks that open up when the engine is hot to any one of a number of carburetor issues.
even issues with vacuum thermo switches, faulty heat risers, etc. etc.
