My car backfires loud when I get up to about 70 on heavy accel. then close throttle and then as I'm slowing down I can hear little ones. Also when I'm coasting on highway and give it some gas to accelerate a little, right when I press the gas I can hear some backfiring, but just for a second and it's only like 2 or 3 little ones. Any "usual suspects"?

 

Have you done anything to the engine lately?

 

nope, just got it back from all new motor bearings (cam,main,rod) being put in and it's been doing this for as long as i can remem. now since im going straight pipe, I can tell its a backfire.

 

did they put the opti in right or mabe the opti going

 

If it does it only after you let off the gas then its normal.

 

too much/too little preload maybe

 

It does it when I press the gas coming off a coast at about 60 or more.

 

sounds like regular exhaust pop, just unburnt fuel detonating a little late