Vacuum lines all checked using a vacuum pump.
all vacuum lines Ty wrapped to make sure they stay sealed.
SC feels good normal play when moving back and forth.
MPS system, car came with 3.4" and I moved to 3.6" within a week of getting a car, 3.8 about a week later from a member here.
Scotty suggested MAF may be bad even though there was no evidence of a problem. Replaced it with a Delco
was getting P0068 it was suggested that the MAP may be bad swapped Map and Baro no change.
bought mechanical gauge and installed it to see what was going on.
boost would shoot up then PCM would dump boost
connected fuel pressure gauge 65psi all day long. Bought an electric oil pressure gauge and unscrewed the mechanical fuel pressure gauge and installed oil pressure sender and ran wire into the cabin. Ran for 3 days with 65 psi all day every day
removed the fuel pressure sender and connected a micro switch to detect if it opened or not. Connected the other end to my multimeter set to continuity and grounded other end. Beeps when the valve closes. Found when climbing hill that I would get to 5psi then drop to 0 valve would open.
suspected that previous owner had it "tuned" and screwed it up. Installed stock 04' GTP computer and that's where I'm at now. With the 05' PCM the car went dead lean every time I got on it.
because its adding fuel to drown out knock hence why you don't see it knock... Cmon man all these symptoms lead to a demolished bottom end.
In the above post I quoted where did you check 180psi on all cylinders or is that a guess? They were all exactly 180? LOL What happened to plugs that were replaced or were they? also not mentioned in the above post?
You checked oil pressure, good for you still a junk bottom end... computer is compensating timing and fuel trims to make it run with out knocking. (back to stock pulley helps reduce the drastic changes the computer has to do to make it run and idle with out knocking well sort of run that is)
Lets rule out vac lines, SC, bbv, sc coupler, all sensors, unless its still throwing codes? rule out the pcm since it apparently idles and drives sort of.
Id love to see pics of the plugs and pics of the cylinders after you pull the heads.
At this point you don't have much to lose, pull heads and the cylinders look fine and you button it back up and rule out a bad bottom end which I highly suspect is the issue, Or you pull heads and see one or a few demolished cylinders and replace the engine and be happy you have a running issue free car......
Until you check the plugs or pull the heads everything else is a waste as far as im concerned and your just chasing yourself around in circles.