hi just need some help ive got a 1993 wrx classic had it two weeks it started backfiring(popping) when you let go of gas.It never used to do that before and is running a bit rough like exhaust is blowing,making a sound from middle of the exhaust,got the car checked out the exhaust is fine doesnt smoke.turbo seems fine doesnt lose water or overheats can anyone help

 

Has it got any mods like DV & Decat?

 

its got a decat and a dumpvalve and a cone filter vjust waiting for a standard airbox to be delivered.

 

Running rich maybe.

 

how do i check if it is and also noticed the turbo kicks in proper after it reaches about 4000 revs any suggestions people