leak down is, will it hold pressure after the engine is shut off and key is off. yes wide open throttle. want to see if its going to high or to low when max demand is make. with your car im not sure the pressure. need a book. mine calls for 41 to 47 psi. should drop 3 to 10 psi when running.

 

OK, didnt read the entire thread, way long. However, I had the exact same symptoms in my 1986 305 tpi transam. Swapped out the MAF sensor from my 1987 IROC, problem dissapeared (after replacing an otherwise fine O2). Funny thing is, if you unplug the maf on the 305, car basically wont idle, whereas, on the 5.7, it will even run down the road, just no power and engine begans to heat up.

 

One more thought, if you are going to replace the fuel regulator, i have two suggestions. First and since the plentum has to be removed for access to the fuel regulator, I would spend the $75 and replace the EGR as well-even if the current one is working-make use of the time/labor since the plentum has to be removed for both. Second, I would go with an adjustable fuel regulator, such as maybe a Holley. The addition of 5-10 lbs of fuel pressure is the cheapest HP add on you can do for these TPI motors.

 

ok fellas, it's been awhile..here's my story. So we know a friend of a friend that's supposed to be a really good mechanic. He came over, didn't discover much. We tested the TPS voltage, and from what I could find online, it looked like it was within range. It's been long enough that I don't remember what the read is, but if it would help you help me I can take another read, I've still got the meter. Anyway, he said he thought it might be the MAS. I realize there's not really a way to tell if it's bad or not aside from taking a voltage reading and checking if it's within normal range. This friend mechanic guy says he had a meter to test this, but I have been unable to get ahold of him for months.

I didn't want to spend the 200 whatever bucks blindly to replace a part that might not need fixing, but I figured I'd check with you guys. Part of me feels like this has to be it cuz there's not much left, but at the same time with everything I've done with no improvement it wouldn't surprise if that did nothing also.

I realize you all probably forgot about this, but if anyone has any insight it's still much appreciated.

FYI, another reason i've been absent for so long is cuz the my monte just died on the way to work, all of a sudden. Motor is shot, just like that. Getting a new motor in that, and in the mean time bought a 04 4 door cavalier. Yeah I know, zoom zoom badass, right?