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

High idle

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Old Apr 13, 2024 | 04:21 PM
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Default High idle

When I crank up car idles at about 13 to 14 then would drop down to 5 to 6 now it stays at 13 but drops to 8 when goes in gear thanks for any help
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Old Apr 13, 2024 | 06:43 PM
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Have you checked around upper plenum for vacuum leaks? Spray some starter fluid around the gaskets of the runners to plenum, throttle body to plenum and plenum to lower Intake manifold and see if idle spikes.

If you don't find any leaks, it could by the idle air control sensor needs replaced on the bottom right of the throttle body, easy rip and replace part.

Finally have you done any maintnence lately that could have messed with the timing or the throttle body? Both can contribute to off idle.

​​​​Also the dash may be less than trust worthy, if you haven't changed anything an can't find anything wrong above, could be the dash is inconsistent vs the computer reading? Keep in mind to search the forums, there are a lot of other threads on similar issues depending on where your troubleshooting takes you.

Let us know what you find out!
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Old Apr 14, 2024 | 11:45 AM
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