93 z28, problem? Please help
It's comical you have a high-flow cat, and no cat, but Flowmasters
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Anyways, to the OP:
I don't remember replying to this thread lol So on that note...
The black gunk is on the throttle body or the air filter? If air filter, inside or outside of it? Outside: If it's a K&N it's just how they get. Inside: I don't know lol That's a bit strange...
If it's in the TB, then it's from the PCV most likely. TBs just get like that :\ The intake is usually worse.
The backfire w/o a cat could be due to less back pressure, but I just can't see, with how crappy a Flowmaster flows, not creating enough back pressure.


