Sorry in advance about the long post but I am frustrated and looking for some advice.
A little info on what I have going on: I have a '99 GTP that I bought about 2 years ago with 140xxx miles on it and overall ran fine. CEL was on and it was P0171 lean code bank one, could never figure it out, all new vaccume lines etc. I replaced the lower intake manifold about 10k miles ago. Since day one the car had a surge at full throttle in 2nd 3rd and 4th gear at 3.5k+rpm and cel would flash (misfire) last month engine spun a bearing and when I was under the hood checking it out I found a leak in the egr valve tube that goes to the intake it had about 165k miles before it died.(maf, tps and iac were replaced when I bought the car)
Anyways I bought a newer engine out of a 97 gtp with 93k miles on it, before I put it in I replaced the LIM gasket and oil pan gasket, swapped out both knock sensors with the ones from the blown up motor because the ones that came with the newer motor were broken, I reused the crank and cam sensors, O2 sensor and EGR valve that came with the new motor and reused the coils, ignition module throttle body and sensors from the old blown up engine. I went ahead and replaced the spark plugs with some NGK tr55 and left the gap at .060"
Swap went smoothly and had the engine running within a day, it started right up and idled smoothly with no CEL. By this time I was extremely happy. I took it for a test drive with the hood off and felt like a complete ricer LOL. I noticed when giving it some gas like ½ throttle it surges and hesitates to rev up as well as in full throttle it surges and hesitates a lot as wel to the point where it has no power at all.
I have a ’00 gtp with 108k miles that runs great and pulls hard and started swapping out parts, I have replaced the coils and ignition module with not difference in performance, I thouht maybe an injector was bad or maybe bad fpr so I swapped them out and also no changes, replaced even the MAP sensor and nothing, today I checked fuel pressure and prime pressure is at 50psi, idle pressure vac-on is at 48 and vac line disconnected is at 52psi. Fuel filter is about 10k miles old and fuel pump is an intank walbro 255. I sprayed some carb cleaner around the egr valve tube that goes into the LIM and made the engine stall out so I fabricated a block off plate for the intake and one for the valve, I put some rtv on the intake one, took for a test drive and same thing.
I am completely clueless as to what it could be now, I am not getting a CEL but obviously car runs bad and lacks power, the surging and hesitation is worse than with the old motor. The only two things I can think of is a faulty MAF sensor with no code OR a bad PCM? Are the ’00 4 door GTP PCM the same as the ’99 2 door pcm? I might try swapping them out to see
Any help would be highly appreciated as I am confused on what else to do
