Just wanted to throw in my two cents, I had this SAME EXACT issue (might not be the same underlying cause) last year, I know you said you changed the MAF sensor, but I would suggest, unplugging the connector from the MAF sensor while the car is running (and is warmed up, giving you the issues you're describing), and see if the engine suddenly stops choking on itself. Your problem is exactly the way mine was -- when the engine was cold everything was golden, after it warmed up and I turned it off and started it again, problems galore with it stalling out!

May not help you since you did change the sensor and all, but it's worth a shot. Yes, it will throw a code too when you unplug it but it's nothing to worry about since you know why it's doing that.

Ended up needing a new MAF, you could be having a MAF sensor issue still, or for that matter, a wiring issue that isn't giving constant readings back to the PCM.

I would like to mention my fuel pump was in the beginning stages of failing at the same time and just about two months ago, it finally died on me -- I really don't think the fuel pump had anything to do with it at the time, but I thought I'd just throw that in as food for thought.

Sorry that didn't work out for you; as Chico suggested, your fuel pump pressure could be falling off when warm (something one of those five mechanics should've checked ). See my comments on fuel pressure here . You can also try the Temp Fuel Pump Resistor Fix (It's free and reversible). Check for fuel in the fuel pressure regulator vacuum hose, and make sure each injector harness is connected to the correct injector/cylinder.
Other possible causes include, but not limited to: Leaking/faulty injectors, faulty ignition module, TPS, MAP sensor, EGR system problem, vacuum leaks, exhaust system blockage or restrictions, problems in any of the related wiring harnesses.

okay so I just took the car for a spin and let it warm up. Got home and unplugged the MAF and it didn't stall itself out. When I went to plug it back in it kinda chugged a bit but still didn't stall. With it unplugged it started up fine..waiting a few minutes to go back out and try starting it again with the MAF unplugged and then again with it plugged in.

if it runs better with the maf unpluged chances are then it is eather dirty or shot, you can try to clean it but that is a temp fix and just best to replace it .

http://www.zzperformance.com/grand_prix/products1.php?id=378&catid=107

edit .. dont use that link u have a 97 thats for 99+

is it okay to drive with the maf unplugged? any way I can bypass it altogether?

unplugging it is a very temp fix and no there is no way you can buypass it because it moniters the amount of air that goes into the intake, by unpluging it it goes off of what the pcm says i think.... but you SHOULD NOT drive permanately without it if you order one and hook it up you mpg should improve as well because of proper readings

grrr...how did I get a bad one? OKay, so buy another one and try again...will do tomorrow then. Poor car!

you have allready replaced once ??

Check the MAF sensor connector for backed out terminals or poor wire to terminal connections. If it runs bad with the MAF plugged in, try wiggling the wire harness; make sure the TPS and MAP sensor connections are secure as well.

just to let you guys know, it is the fuel pump and leaking injectors. Mystery solved, but about 800 canadian to remedy the problem..too bad I couldn't find a good mechanic in the first place. Well at least the car has a lot of new parts. Getting fixed on Wednesday.