9165pt0

hey guys just wanted to know if anyone can tell me what causes this: wheneva i take my car up to around 4k rpm and let off the throttle and just roll, the exhaust will make a popping noise a few times while the rpm come back down? just wanted to know what makes it do that and if it has any negative effects thanks. btw i have some eq. length shorties, h pipe, n flowmasters on it.

90mustang5.8

backfire? its pretty much normal

w8less

backfire is not normal

90mustang5.8

i think of it as normal, almost every car does it when coming down from high rev

9165pt0

thanks guys, so will it hurt anything or not?

chath_brick

you're probably running a little lean. it wont hurt anything.

945LSTANG

mine did that for a while, when i removed the smog pump i noticed that it didnt happen quite as much. your issue is normal btw.

94Blk5.0

I think what you are referring to is called "backing down". The motor is just being slowed by the drag of the drivetrain. If were talking aboubt the same thing, I always thought that was cool.

1990mustanggt

Are you sure you don't have any exhaust leaks anywhere? That could cause popping/backfiring.