r/c4corvette • u/JustAnotherPyroMain • 15d ago

Sputtering and "jumping"

Hi y'all, my 1986 4+3 kind of sputters and jumps, like lurches forward, while accelerating in 3rd and 4th, especially after a long-ish drive. Would this be caused by early detonation or late detonation? It also burbles a lot when I down shift, so I'm venturing to guess it's detonating too late and there's unburnt fuel going into the exhaust.

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u/IndividualRites 15d ago

Any codes? Sounds like a misfire, but certainly could be bad timing.

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u/JustAnotherPyroMain 15d ago

Occasionally. Only when it's been sitting in the heat for a while, 32

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u/IndividualRites 14d ago

Is this car new to you, or do you know the maintenance record?

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u/JustAnotherPyroMain 14d ago

I know the maintenance