I have an 05' GTP and have been having a lot of issues with it. Most I have figured out. I keep getting a P0069 MAP and Baro correlation error. Well that's all well and good I understand what it means. This is what I have tried so far.
Added a boost gauge to see what the manifold pressure is. This is Teed into the MAP sensor. 18-20" at idle
Viewed the freeze frames and the Baro shows 29.5" the MAP is always showing 18.5"
Bought a Wells MAP and the car didn't like it at all.
Checked the voltages at the devices have 5V, .5ohm to ground and the signals are where I would expect.
I bought 2 new sensors (same for both) changed the Baro no change, changed the MAP and it ran better.
I was able to get into boost just rolling on the throttle getting up to about 5psi then just cruising. Did this a few times and then I started having the stalling and not able to go into boost (basically it would die like it's super lean or rich) it sputters and spits and I have to drop down a gear or 2.
I played with the hoses around the MAP because I noticed that in gear I had lost about 2" Hg. Seemed better.
I borrowed a more advanced scanner and watched live data of the sensors. MAF seemed normal map showed about 10" which was way off my 18" on my gauge. Baro was holding steady at 29.5". I varied engine speed and it seemed to respond. I put another MAP and got higher readings in the 12"-15" range then played with it again and got it to 18" and the gauge reading a solid 20".
Thought about it and figured 10 year old hoses so I replaced the short piece that comes out of the nipple to the filter with the two outlets. I used wire ties and a ty wrap gun to secure the hose firmly. I did this with all the other fittings both sides of the one leading to the bypass solenoid and all the ones on the T for the boost gauge and MAP.
I thought that the short piece of hose leading to the filter splitter thing was really cracked.
After that the car ran pretty hard and didn't stall I took it to 7-8psi a couple of times and it did pretty well but seemed to lay over(lose power) pretty quick and I let off and cruised.
I've driven the car around about 150 miles and it is running pretty good but I ran codes on it when I got home and the damn thing is back! It hasn't set an MIL but it shows on a scan.
I'm really at a loss, I have checked every vacuum fitting and everything is tight. The car runs pretty well but will not go into boost anymore. I can stomp it and the RPMs will come up and the tires will spin, but the boost gauge shows 0. I can roll onnit on the freeway and it will go to 1-2psi then drop to 0. I can kick it into passing gear and it will show 0, sometimes it will come up to 5psi then drop to 0.
Thanks,
Jeff