# Why does leak cause misfire?



## SigEpbro33 (Aug 24, 2007)

Im bored at work and just thought about why would a leaking valve cover gasket cause the spark plugs to misfire? The plugs are inside the cylinder, along with the gas. If more air was being sucked in from the gasket area wouldnt it have a higher idle and then just die? That was the case on an suski outboard motor i was working on. So any insight besides "thats just what happens"?


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## dfreeman616 (Feb 15, 2007)

additional air through the pcv system, which is after throttle body. this creates a lean misfire where there isn't enough fuel to burn properly. it would have to be a pretty good size leak though.


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