i had to have my heads pulled cause i blew a head gasket and the heads got wraped. so had them cleaned up and ported for my blower. put 1.6rr on and left the blower off so i could adjust the valves and started the car up without the blower on and all was cool. i hook the s-trim back up and now at idle random backfire happens? head work-maf put back in stock location and kn valve cover breather,1.6rr are the only mods i did. but the blower running is causing the backfire. no check enigne lights either, car runs good.