Hi guys. New here.

The wife has a 99 GTP and it will sometimes just stall. Sometimes it won't start....it will turn over just fine but not fire up. She also mentioned a "lurching forward". I am assuming it is all the same problem....hoping rather.

I am also hoping this is a "common" issue and has been discussed and diagnosed here before. Any help is greatly appreciated as I would like to buy parts and fix it tonight if possible.

possibly the maf sensor. next time it won't start, try plugging the sensor on the very top of the throttlebody, right where the intake ducting attaches, and try to start it again.

if that works, try to find one for sale on the forums for cheap rather than paying a tonne from the store. they are pricey.

Thanks. I was sure the MAF would cause stalling and "lurching" but was unsure if it would cause it to not start.

Parts Source has a MAF for $128....and I need it ASAP as it is getting worse by the day.

So, I swapped out the MAF (was a remanned one if that matters). Everything was working fine. Took it for a test drive and from a slow speed, I floored it and it died. Made some strange clicking noise as it tried to keep idle. Started it, died. Started it, died. Started it and gave it gas to keep it alive and it was choking...perhaps starving of fuel?...don;t know. Died. Started it up and it ran perfectly.

Does the computer have to re-learn when a bad part has been replaced?

Not always, but there are a few things, like fuel trims, that are always being self-adjusted. Since it stalled, I would think that the issue lies somewhere else. Has it been throwing codes?

Codes?

Do you have a fuel pressure tester that you can put on the rail to see what the pressure is like when you're having the stalling problems.

I don't have a pressure tester...and the CE light has been on for 2 years....EVAP something. Maybe there are new codes I will check.

probably EVAP flow during non-purge. Problem a hole in the line, no biggie, but I would have it checked to see what else is there.

runs for a split second and dies?

Try this
bypass the fuel pressure resistor



Pull the relay bend tab 85 so it won't go in. Reinstall the relay and start the car. If that works the resistor is bad and needs replaced or you can leave the relay as it is and go on without any worries.

Where is that fuse box located? Under hood or in car?

Under the hood, passenger side strut tower.

That one looks to be on the passenger-side strut tower, under the hood.

I was thinking fuel pump resistor but I thought that was only 97 GTPs... guess not.

I had it go out on my 98. Drove like that for a year and a half before I put a new resitor in. And I think the resistor was used on GTPs till 00. In 01 they did away with them.

So I did the fuel pump resistor trick this morning and the wife said it did not stall at all today on her way to work.

My question is, can this problem be intermittent or would it be a constant issue?

I just replaced the fuel pump relay again last week. I put a new one in back in '04 when I replaced the fuel pump, stashed the original one in the glove box as a spare. (My GT only has one relay and no resistor)
The relay would click on to prime the pump, then the engine would crank over and not run. Swapped in the old relay, and the car started right up. So now I have a couple of spare relays in the glove box..

Hi DaTT,

Those resistors were a high failure item on GTPs, so if the car no longer stalls, you've found the gremlin. If memory serves GM has a resistor relocation kit, and there's also an aftermarket wiring harness that bypasses the resistor: Caspers Electronics Fuel Pump Hotwire Kit

Or you can just leave the tab 85 bent out and not worry about it. And it's the resistor that goes bad not the relay. Well 99.9% of the time.

Problem not fixed.

Found the fuel pressure regulator and unplugged the vacuum line while it was running to see if that was it...nope, didn't stall.

What about fuel pump? I am going to get a pressure gauge tomorrow and test it. I have never done this before, so I assume it goes into the spot on one of the rails that has a black cap on it. Does it just screw in? Any precautions I should know about? Just screw it in and let it run and monitor fuel pressure?

Thanks

So it stalled again?

It won't necessarily stall with the vacuum line pulled off the regulator so I'm not sure what you were testing there.

I guess I was just trying to duplicate the problem. I am leaning towards fuel pump at this time.

What pressure should I be seeing for this engine?

For fuel pressure

http://www.grandprix.net/forum/ubbthreads.php?ubb=showflat&Number=107183&page=2

Thanks. I assume the pressure should be the same with the engine running? I am also going to test the regulator, there is no fuel leaking from the line, is it still possible for it to be bad?

Checked pressure. Here is what I got:

****Fuel resistor bypassed to run in high speed mode***

-Key on engine off = 46psi, sometimes 42psi (did several tests)
-Engine running = 50psi, sometimes 46, sometimes 42

Pressure would jump when throttle was applied, I assume that is normal.

-While engine was running, I d/c'ed the vacuum line for the regulator and the pressure jumped up by 2psi the first time. Repeated the test and it jumped up by 10psi (normal).

CE light had come on and I got the MAF code.

Cleared the code and used some Sensor Kleen MAF cleaner, re-installed and it seems to be fine now. But I doubt it is fine.

Car stalled and I noticed the TCS OFF light came on. I can not be certain if this happened before because I never looked up there.

Could be a faulty Crankshaft Position Sensor, here's a write up: Crankshaft Position Sensor Replacement

So, I lost tach and TCS OFF light came on. Thought the car had stalled so I turned the key only to hear that nasty grinding noise.

So, is the CPS the only thing would cause loss of tach and TCS light on? Also, would it throw a MAF (P0102) code? Also, would it cause the car to buck violently under throttle....this only happens sometimes.

Thanks for the link....any idea on how long it takes to complete?

Tach going crazy/dieing sounds like the CPS. As for the TCS light these cars are very sensative to wierd power. With the car stalling etc it could cause power drains and surges and throws things for a loop.

But the more I think of it with multiple unrealted issues leads me to the ignition switch.

The GM dealer near me....I spoke to one of their Diagnosers (word?) and he also said ignition switch. He told me to start the car and smack the key around to try and get it to stall. I did this and could not get it to stall.

This car is starting to remind of my 1990 Thunderbird SC.

The part of the switch that fails is the electrical component not the key cylinder.

3:1 odds its the crank sensor. Usually ignition switch will cause more issues than just stall/loss of tach. Those are classic CPS symptoms. See this thread for my suggestion on making your own harmonic balancer puller: http://www.grandprix.net/forum/ubbthreads.php?ubb=showflat&Number=213845#Post213845 . It's really a pretty easy job, but your first time plan for it to take at least a couple hours. Worst part is the crank bolt. Move your coolant reservoir and fuse box out of the way and go at it from the top, using a long cheater bar. Make sure you clamp some vice grips on the flexplate to prevent the crank from turning.

Would placing the breaker bar against a solid object and bumping the starter an idea on these?

I've heard of guys doing that too. Will only work for removal though, still have to get leverage to torque it back on when finished with the repair.

Doesn't it all come as one piece? That's the impression I got from the dealer guy.

It's the bucking it does sometimes too, with a very audible clicking coming from the passenger side under the hood during the bucking that led him to say ignition switch. Relay getting 12v then 0v then 12v then 0v

No they don't

Here's a good write up on how to change one

http://www.automotiveforums.com/t653340-how_to_replace_ignition_switch_97_03.html

Here's the part in question

I have a grand prix gtp/ it stalls from time to time but I just go get another keyswitch with new keys from oreileys- about 14.00/ I bought lifetime warranty and so far now in 2 1/2 years replace 3 key switches/ the first time my son replaced it/didnt solve problem I said maybe the switch was manufactured bad sure enough it was. so now its I had to replace the key switch twice. it stalls out might wait a few moments then it will start but you can always tell when it goes bad because it will act like trans is kind of slipping sure enough after about a week it starts to stall. I dont know if there is a more serious problem I only know every time it does it I get a key switch and its good to go

Thanks. It is currently at GM for a diagnosis. They have the proper equipment and I am at a loss....I can't just start throwing parts her way. I'll keep you posted.

BTW....a MAF at the dealer is $591. WTF??!! Its a piece of plastic with a couple resistors.

^^That's the dealer for you, Rock Auto has AC Delco MAF sensors for $199.79 (new) and $158.79 (reman) with a $63.00 core charge. I hope they can find the problem with the car.

Japan crisis must be driving up prices, I replaced mine a couple years ago and it was around $150 for the AC Delco MAF.

I found an ignition switch from a 2002 GT. Will it be interchangeable with my 1999 GTP? The 2002 has pass key III and mine has none.

anyone? I will go get it tomorrow if it will work

It should work, as long as both cars have floor shift (some GPs had column shifters).

OK, found a good MAF (so far....been 4 days with no codes), however she still stalls out. I can't decide if it is ignition switch or crank position sensor, or something else.

Stalls when driving sometimes at any speed. TCS OFF light on and loss of tach (sometimes).

The thing is, I can't get it to do this, only happens when she is driving. I wonder if my best bet would be to take it back to the dealer.

I'm gonna say crank sensor. TCS pulls timing to help gain traction if it's getting faulty info from the crank sensor for timing it would turn the TCS off.

I finally might have the problem solved. Pulled into my driveway and noticed the tach gone and TCS OFF light was on so I decided to check the code BEFORE shutting the engine off. Sure enough, P0336 Crankshaft Position Sensor out of range. I think i read somewhere that this code will clear after the next startup if it passes 4 consecutive tests which would be why I have never seen this code.

Same thing is happening with my '00 - car is in the shop for the 3rd time right now because the car would never act up for the mechanics.

HOWEVER, I figure out exactly when/how it would act up so I took it back in to them - the car must be cold and must have been sitting for several hours! The car only dies (or occasionally the tach drops to zero but the car still runs) when it has not been cranked overnight or during the day while I'm at work. I drive 3 to 5 miles and it dies and will take about 2 or 3 minutes before it will restart. Once its restarted it won't die again until it's been sitting for a long time.

So I've been driving a mile or two and then pulling off the road, turning the car off, sitting for a couple of minutes, then restarting it and it won't just die on me. Weird, huh?

Well, I left it overnight at the shop and the mechanic drove it yesterday morning and the tach quit and the trac light came on, but the car kept running. He got no reading, but thought it might be either the cam sensor or crank sensor. I left it overnight again and, sure enough, when the mechanic drove it this morning it died! He had it hooked up and it was diagnosed as being the ignition control module.

Unfortunately, they want $450 to install a $129 part ... I don't think so.