check over all your couplings and make sure they are all tight and nothing has come loose.

If it's smoking while you're driving, then it's either burning an excessive amount of oil or its burning antifreeze, and if it's burning antifreeze then you've got a problem with your head gasket, which could also be the source of why it's not running properly.

But hopefully you just have a leak in your chargepipes somewhere and the smoke is coincidence.

OP. was the smoke a thick white smoke and did it smoke while you were driving it. Also, with boost leaks you will notice sputtering as your turbo starts to spool

If you're suggesting because of its northern geographic location that the temperatures in the summer time are cold enough to promote tailpipe steam in the mornings, then that's kind of silly. I live in CT, and last I checked that was even farther north than New Jersey.. and my car's tailpipe doesn't emit steam in the mornings until well into October.

and no, obviously merely starting the car won't blow a head gasket. They go bad over time. Being a "worst scenario" kind of guy, I'm suggesting that it isn't unreasonable to think that one of his last trips out that a bit of head gasket may have finally deteriorated enough and that while parked the pressurized cooling system forced a bit of antifreeze into one of the cylinders, which is causing the smoke and is now lending itself as a path for combustion gasses to go which may drop psi on one cylinder to cause the rough drivability.

but like i said, I'm not specifically an optimist.

Modified by Neil at 12:51 AM 8/14/2008

Autozone or Pepboys or someplace may be able to rent you the gauge and adapter. Let the motor warm up, then pull out all the plugs and check each cyl one by one. I'm not positive what the #'s are supposed to be but rule of thumb is all 4 cylinders shouldn't have more than like 15% variation between them.

so say for example if compression is supposed to be 145psi, if you get like 134, 130, 107, 138, then obviously cylinder 3 would be having troubles. also the color of the spark plugs themselves can tell you a bit about what's going on.