Revs fine. Has a good idle. Engine is in great condition. Replaced the plugs, wires, and coils. Helped, but didnt fix my problem. At about 5psi of boost it just starts sputtering out the exhaust. It just doesnt want to make more than 5psi. Checked all the actuators. Connections were good. No boost leaks. No vaccum leaks. No nothin. I have no idea what it is and I've checked everything, even the MAP sensor. Oh ya - it smokes white at idle (a pretty decent amount) and black when I romp it (again, a pretty decent amount, but not huge clouds of it). I checked the front turbo for shaft play and its in fine condition. Rear turbo I dunno. Previous owner said it had 8k miles when I bought it, so thats about 10k now. Anyone have any ideas on where to go next?

 

Engine has 12k miles on it built by a reputable shop. This doesnt sound like its related to the engine in any way does it?

 

Just checked the coolant level. Hasnt been touched in the past 3k miles that I've owned the car. Still full to the top.