so ive been in AZ 8 months and had my car tuned by a friend of mine back from IL (owns a house out here as well) so he was out here on business back in august and he tuned my car and the car ran great. now this past november whenever i punch it before it hits full boost it stutters and back fires, but then evens out. has blown out some smoke but cant tell what color it was. if i ease into full thorttle it doesnt stutter as bad but still noticeable. ive changed the plugs, ran sea foam, and fuel injector cleaner. my mods are apexi TBE stock evo 9 BOV O2 housing walbro 255 fuel pump and boost controller. stock turbo. please any ideas you guys have and a well known shop that could fix whatever issue i have.

thanks in advance,
Mike

 

Deff sounds like something with the fuel...seems to me like you have a build up with the fuel during spool up and that backfire is from all the fuel building up and then burning off in a sudden burst. Car might be running real rich after the tune. I would go back to your friend that tuned it and diagnose the fuel system.. Sounds like your Air/Fuel curve is the problem its not delivery the fuel correctly

 

Checks your coil packs and also your plug wires. sounds like an ignition problem and not a fuel problem. Make sure your plug wires arent grounding out to the head