C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

rough idle only when cold start

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Old Jul 4, 2012 | 04:38 AM
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Gene Warn's Avatar
Gene Warn
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Default rough idle only when cold start

i have a 92 corvette when i start it in the morning or after it sat for awhile runs really rough almost dies just at idle but after driving for awhile it smooths out and runs fine can someone please give me some ideas ive changed plugs wires most sensors.did not do that till i had a injector go out took it to shop they changed it and now rough idle they checked everthing said what they did was ok please help
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Old Jul 4, 2012 | 08:47 AM
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Originally Posted by Gene Warn
i have a 92 corvette when i start it in the morning or after it sat for awhile runs really rough almost dies just at idle but after driving for awhile it smooths out and runs fine can someone please give me some ideas ive changed plugs wires most sensors.did not do that till i had a injector go out took it to shop they changed it and now rough idle they checked everthing said what they did was ok please help
Gene, the first thing anyone will ask is if you or the shop checked codes. there is a thread on this page with instructions on how to do it. "'89 codes" or similar. if you don't have it already, SAVE THE LINK. codes issues are one of the most common problems on this forum -that, and "no start."

I am not an lt1 owner, so won't volunteer anything to confuse you. but start with codes.

joe
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Old Jul 5, 2012 | 02:28 AM
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Gene Warn
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thanks but not throwing any codes
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Old Jul 5, 2012 | 05:47 AM
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Check the vacuum line connections against the diagram in the engine compartment. When I got my 84 the vacuum lines were all screwed up and I think there is something that the charcoal canister purge solenoid does when the engine is cold that can create a big leak if its not connected right. It does not take long to check and you would be surprised how many cars have their vacuum lines wrong. Maybe it happened while they were doing the injector work.
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