Hi I'm new to AF. Have read a lot on here and now have problems of my own. I have a 2001 GTP with 151,000 miles. Car was running great on a 5 hour trip and pulled onto an off ramp and stopped then when I went to take off the car was jerking back and forth and reved up to 5000 RPM and wouldn't shift until I let off the throttle, but the car was still gaining speed. Next morning car was running fine then started acting up again, just like before. Got home and hooked up the code reader and got a P0101 and a P0121 codes. So If I erase the codes the car seems to run bettter for a bit then throws the same two codes again. Cleaned the MAF and also tried another one out of a 97 GTP, and that didn't help. Tried a new TPS and that didn't help either, actually ran worse. I read the threads about the Cat pluging up on the 01 so I deleated it and the resanator last night and it ran great for about 12 miles then threw the same codes again and then died. Also before taking this 12 mile trip I also got a P1810 code which is ATF Pressure Manual Valve Position Switch Malfuction. The car was up on a set of ramps though at the time. Started back up and ran rough. Took off in it a hour later and ran fine back home. I also can't get the boost gauge to read past 4 bars now. My cousin has a Snap-on Scanner we hooked it up to and everything looks great even when it was acting up. I'm really confused on where to go from here and wonder if the computer is bad. Any help would be great!! Ask me any questions you may have!

Welcome to AF.

Try disconnecting the MAF sensor, clear the SES/CEL light and DTCs and then see how driveability is. A MAF sensor from a '97 GTP may not work. Control substitute with '99 and up only.

Is the P1810 TFP DTC still present or just a fluke due to being on ramps? When the transmission fluid pressure switch goes bad symptoms may be a neutral flare and/or RPM increase while in drive or no 1-2 upshift.

Thanks for the reply!!! The P1810 code has not come back! I'm going to try to unhook the MAF tonight and give that a try! I'll let you know! Thank you!!!

Just got back from a test drive. Unplugged the MAF sensor and the car started idling up and down and then threw a P0102 code. Plugged back in and erased code. Drove for another 2 miles to let warm up and then unplugged again and the car died. So I plugged back in and headed home. Got into town and had to slow down for a SUV in front of me and car died, then died at a stop sign. Started right back up and idled fine at the next stop sign and when I got home also.

Just to clarify, unplug the MAF with the car off not running. Start it and let the PCM adjust for the lack of MAF signal (it should throw a code because the MAF is unplugged) then try driving it. If it runs better with the MAF unplugged after the adjustment period, you need a MAF. If nothing changes, check the wiring between the MAF and the PCM for any corrosion, broken or exposed wires. One last thing, does this car have any mods?

I will try that after work. I bought this car about 5 months ago so I don't know if it has been modded or not. I do know that the car will do 125 mph and still gains speed. I don't know what the speed limiter is suppose to be on an 01'. So I don't know if the PCM has been changed or not!

The speed limiter is programmed for approximately 128 mph for GTP only. Does it have a CAI/FWI intake or stock airbox and filter?

To see if the previous owners(s) installed a re-programmed PCM open up the airbox and look for a label affixed by the company that did the programming. If a PowerTuner was used for custom programming probably no label. Other easy ways to tell are the programmed shift points in automatic at 5800 rpms. Stage 1 DHP, Intense or ZZP PCMs have no speed limiters but shift in auto at 6K rpms. Also, do the coolings fans come on at 180 degrees or do the cooling fans run for a few minutes when ignition is turned off.

No label in air box or anywhere! It sometime shifts at 5500 rpm and sometimes it hits 6000 rpm. I have never paid attention to the fans and what temp they kick on! And no they don't run with the key off!

Then you and we can assume you have a stock PCM module. Any other mods like intake or exhaust? Cold Air Intake? Does the input of the throttle body have the inlet screen installed?

No cold air intake! Has a K&N air filter in stock box. Only mods are the cat and resonator removal which I did a couple of days ago hoping it would help. I've had the air inlet screen out since I bought the car but reinstalled it after starting to have these problems. Has new plugs, wires, and fuel filter. Car runs great when cold and then starts to act up when it gets warm. I'm going to try the MAF again tonight but what are the chanches that is messing with my boost and shifting problems? What are the signs of a bad PCM? Thanks a lot everyone for the help so far!!!!! =-)

Ok, got home disconnected the MAF, started the car and let it idle for 10 minutes. Idle sounded alright then it surged a couple of times. Got in and went for a test drive and the car died at the first stop sign I came to. Stopped or coasting the tach should bounce between 100 and 1000 rpm, and die most of the time. Have to start back up and would have to keep giving it gas until I could take back off and it would then have no power , then just take off. The dieing thing is getting worse everytime I drive it. So I don't know if that means that the MAF sensor is good or not!

correction for last post above ---- the tach would bounce, not should....oops

Just to rule it out have you checked fuel pressure to see if the fuel supply like the fuel pump is good? How old is the fuel filter? When it stalls/dies any other lights like TRAC OFF?

With the MAF sensor disconnected did you get a SES/CEL light and the same DTCs?

last time I checked fuel pressure it was alright, don't remember the reading now. Replaced the fuel filter about a month ago right before starting having problems. SES light never came on just got the P0102 code on my reader. I don't belive that the TRAC OFF light is coming on when it dies!

What should the pressure be on an 01'?

I'm going to check the fuel pressure in the morning, what should it be? And it that static pressure with the key on, engine off, or engine running?

Can't check pressure until I find my Fuel pressure guage. But I changed the MAP sensor and went for a test drive. Car drove great then threw the P0121 then the P0101 codes and had a rough high idle. Cleared the codes while the car was running and it smoothed right back out and idled at 900- 1000 rpm. I'm so confused and really need this car running because my fiance' and I only have 1 other car that is running and work 1 hour apart and are burning a lot of gas in the blazer.

Have you checked the PCM 5 volt reference signal at the input of the MAF and TPS sensors. Use a multimeter (DMM). Also, check the ground.

No I haven't, I will check here this evening! Thanks!!!!!!!!!!!!!!!!!!!!

Both TP and MAF hase the 5 volts reference. Tp sensor works properly with the increase of throttle the volts go up. The MAF sensor has 5 volts and the signal wire only has 2.4 volts regardless of the engine speed. Also does the MAF sensor control the boost guage? I only get 3 bars on the boost now and sometimes it has 2 bars with the car idling or coasting.

Anyone have anymore ideas?

On the TPS output what are the voltage readings? Idle should be around .45 volts dc and WOT around 4.5 volts. The DTC is a range/performance issue. Also, voltage in between should be linear and progressive with no flat spots as you take it from closed throttle to wide open.

The MAF output is abnormal since it does not change and that respective DTC is a range/performance issue.

Other than ohming out the output of each sensor back to the PCM module to check wiring it looks like a TPS or MAF issue or maybe both. Worse case PCM module. Have you replaced the TPS? On the MAF use one for your year. Only one for '99 and up should be used.

Also, if you have not done so it won't hurt to checkout the idle air controller (IAC). Remove it and clean, lube the spring loaded pintle and the orifice where it mounts to the throttle body.

I removed and cleaned the IAC and have a new TPS on there as well. I hooked up a fuel pressure gauge and when you turn the key on it goes erratic antil the fuel pump shuts off and then holds about 45 psi.

48psi with key on engine off. Engine idling gauge goes crazy.

48 psi at fuel pump prime - ignition on not start appears normal. Are you still getting the same DTCs?

Yes keep getting MAF code. Had on scanner tonight and mass air flow sensor readout was fine. Tried changing the boost control soniloid tonight because the other one was just clicking when we controled it with the scan tool. The fuel pressure regulator is getting no vacuum at all, so we thought that the boost control might be bad. Is there a chance that the PCM isn't controling it like it should and the scan tool is, or can? One other thing the car is running REALLY rich now and will die. The O2 sensor readings for front and rear were all over the place but the front one was going up and down between 71 up to 850 (mV...I think) faster the the scan tool could read out. Still really confused!! =-(

The fuel pressure regulator is getting no vacuum at all, so we thought that the boost control might be bad. Is there a chance that the PCM isn't controlling it like it should and the scan tool is, or can? One other thing the car is running REALLY rich now and will die. The O2 sensor readings for front and rear were all over the place but the front one was going up and down between 71 up to 850 (mV...I think) faster the the scan tool could read out. Still really confused!! =-(

That doesn't sound right. How did you check engine vacuum at the fuel pressure regulator? Was this with an automotive vacuum gauge (0-30 in-hg)? There should be at least 15 in-hg to 18 in-hg there. The vacuum source is off the throttle body. Check it at the throttle body port and check for bad plastic vacuum lines.

The front 02 sensor will read from 100 mV up to around 900 mV after sufficient engine warmup and will change.

Anyone have anymore ideas?

Contaminated fuel perhaps?

I checked the vacuum with an automotive vacuum gague and had no vacuum at all at the FPR . Pulled the hose off of the boost sonoloid that goes to the bypass valve and had no vacuum there either. Have vacuum on the other hose going from the bypass valve to the top of the supercharger. The throttle body has alot of vacuum, I didn't put a guage on it but when we removed the hose it darn near killed the car and was sucking hard. Change the bypass valve last night and that didn't help either.

Also sprayed carb cleaner all over and never affected the engine. And even took the vacuum line off of the FPR and sprayed up in the hose and that didn't affect the engine either.

Do all your vacuum line connections match the illustration below? You should have vacuum to the fuel pressure regulator and boost solenoid. Throttle body output appears good since the engine dies but I'd test it to be sure. With the proper adapter on the vacuum gauge you can quickly disconnect the vacuum line at the TB before the engine dies and connect the gauge. What brand vacuum gauge are you using?

http://i5.photobucket.com/albums/y186/lizzywiz/vacuum.jpg

I FIGURED IT OUT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!! THE MAIN IGNITION RELAY UNDER THE HOOD WAS BAD. i WAS LOOKING IN MY OWNERS MANUAL AND SEEN A FUSE LABELED FUSE 21: MASS AIR FLOW, HEATED SENSORS,CANISTER PURGE, BOOST SOLENOID. BUT IT WAS GOOD, SO I CROSS REFERENCED IT WITH MY FUSE BLOCK COVER AND IT SAID IGNITION MAIN 1. SO I SEEN THE MAIN IGNITION RELAY AND THOUGHT WHAT THE HELL, SO I SWITCHED IT WITH THE COOLING FAN 2 RELAY.....AND BAM IT RUNS BETTER THAN IT EVER HAS SINCE I'VE OWNED IT. THE CAR IDLES SMOOTH, ISN'T RUNNING RICH ANYMORE, I FINALLY HAVE VACUUM AT MY FPR AND BOOST SOLENOID TOO. AND MY BOOST GUAGE IN THE DIC WORKS ALSO !!!!!!!!!!!!!! WHOO HOO!!!!

Thank You To Everyone Of You That Has Helped Me Through This Crazy Time. Your Replies Has Been A Big Help To Me And Tought Me Some Things Too. Maybe If Someone Else Has A Problem Like This In The Future We Might Have An Idea Were To Start. Thanks Again Everyone!!!!!!!!!!!!!!!! =-)