Well, that's sure a mystery hose. In any event, backfiring means unused fuel getting into the hot exhaust and detonating there. So whatever the problem is, it's causing at least one cylinder to fail to ignite, allowing that fuel mixture through to ignite in the exhaust instead. Now if what you're saying is that the cylinder(s) are firing normally but detonating out the intake, that would have to mean a bad intake valve. A valve that doesn't close for the ignition cycle. But I don't see how the compression cycle can complete in that event.
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Last edited by witeshark; 01-05-2009 at 12:35 PM.