wow, thx a ton guys. I'll need to look for this check valve and probably replace. I have a few issues with a couple of hoses on the car, there is one that comes out near the CC module that was cut by previous owner for some reason I think that might be part of the issue. Is there a diagram anywhere of the entire vacuum system for this car? I would search but question came as I was writing :P LOL, nevermind. soon as I hit submit saw the sticky with diagram.  :icon_idea:

Ok. Problem solved. After much aggravation, sweat (I live in phoenix) and burnt and shocked hands I've solved this problem. First plug wire on front of engine closest to turbo was grounding out on the metal tube that runs right in front of the wires. I spent NO money on un-needed parts! Very happy this turned out to be an easy problem to solve. Now. As for replacements. Any suggestions? or just get a universal set from Pep-Boys?

I do have one other question. When I'm driving the car with the air on, air blows cold out of front vents. When I start getting into boost the front vents close and A/C starts blowing out of floor. What causes this? Possible solutions?

Hi all, need a lil help. I tried searching but couldn't really find anything.

1990 TGP w about 130k

Driving home from work last nite and the car starts vibrating a bit under acceleration. I get off the highway and the car seems to be misfiring. Steadily. Doesn't stall. Doesn't try to stall. Rock solid idle over 500 just a constant misfire. I go out and check the coil packs to make sure they are firing, all are firing fine. Get a check guages lite occasionally but nothing regularly. No CEL at all. I pull the wires off each coilpack individually, looking for the one that doesn't change the way the engine runs and couldn't really pinpoint any change in the idle when pulling each wire. I smell raw fuel on occasion since this has happened. Good X-Pipe, no apparent vacuum leaks, and the car has been running/boosting fine. I have come to the conclusion perhaps ignition module/ECM? Where is the ignition module on this car? ECM is behind the trip computer? Any other ideas welcome. I'm usually a pretty good mechanic but as of right now I have NO tools and this includes a spark plug wrench. Nor do I have the cash to pay a mechanic. I need to diagnose this problem instead of throwing parts at it. If anyone can point me in the right direction I'd appreciate it. Anyone with a garage and some tools in the area (PHX, AZ) would be uber appreciated!