when a car backfires, resonating whatever you wanan call it...does that ***** up your internals?? j/w, cause my cat back does taht shiet all the time on 89 octane...

 

It backfires because it's running rich, in other words.. It's not burning all the fuel in the engine, you could have a bad o2 sensor, amoung other things. Do a CEL search and see if that yields anything.

I've never heard of it messing up internals.