Hey Guys,

Ok, so here's the problem. I took my car in for emissions this morning, the car passed fine. But when I pulled the car out of the shop I noticed that any time I stepped on the gas, as soon as the turbos start to spool, the car starts machine gun backfiring. The car runs fine when it's off the turbos, but whenever I step on the gas, as soon as the turbos start to spool (as soon as the gauge goes past 0 heading into boost) the car starts machine gun backfiring and bucking quite a bit. I spoke to the guy at the shop, he said he hadn't done anything to the engine to get it to pass or anything, and I trust him on this, I am pretty sure he didn't do anything to get it to pass. But anyone have any idea what is wrong? the car idles fine and everything, but as soon as the turbos start to spool this problem happens. Any ideas guys???

 

check line to map sensor

 

I'm really a know-nothing when it comes to these cars, but if you're backfiring under boost it means you're not burning all the fuel that's being shot in when the ecu sees elevated pressure levels. Check your plug wires and coils. Maybe the emissions guy was rooting around in there to find a good signal and knocked something loose.