Hey,
I Have a friend with a 2002 Civic SI and an 04 Civic Coupe. The SI has a cold air intake and the Coupe has a short ram intake on them. For some reason if you get on the engine hard at different rpms you hear a loud backfire from the intake. Neither car has any other mods to the engine (no nitrous or anything like that). I have heard about this problem from different friends but was wondering if anyone knows why this is happening to two stock cars which only have upgraded air intakes, and also how to fix it?
Thanks!

 

That's weird I've never heard of an intake "backfiring." What does it sound like? Usually when you talk about backfiring, you're talking about exhaust.

 

try dizzy mine is doing it to and pissing me the fuck off

 

haha, its not you intake. if anything, check your timing. also take the cai intake off and put the stock one one. make sure your vacuum lines are connected to something or blocked, etc