1997 Grand Prix 3800 series II not super charged stalls when driving at low speeds

So I don't understand why this is accruing but my 1997 Grand Prix stalls out randomly when I'm driving at low speeds but if I'm driving at high speeds, like above 35 it's fine I can drive it an 1hr and 1/2 to work and back with no stalling but if I go to the store it will randomly stall out when I take my foot off the gas to turn or to break to park any help would be appreciated thanks
-matt

Last tuneup? Dirty throttle body?

I'm not sure about the N/A version, but the GTP uses a fuel pump resister for low and high load. When it goes bad the low goes out, causing you to stall at low speeds. I would have that checked.

Just cleaned throttle body and it doesn't have the relay for the speed change in fuel pump I'll let you know if cleaning the throstle body works also had some vaccum hoses that we're bad

That resistor is only used on SC'd engines......

Could be bad/dirty MAF....dirty throttle body.......gummed up IAC......

Last tuneup, as asked? Replaced fuel filter? Check vac line to f/p regulator for fuel?

Scanned for codes?

Changed throtle pos sensor still reading code for this and gave it a radiator flush and now it's going to 4000 rpms before it will shift in to second and third we replaced vaccum hoses also and it's still stalling out any ideas

Also only code coming up is the tps

So I changed the fuel filter still no change it's starting to get frustrating because I didn't touch anything to do with the trans but it started acting funny when I notice fluid was low so I put more in till it go up to fill line and still no change any more help would be greatly appreciated

Did you clear the code after replacing the TPS? If yes, it came back?

Yes it comes back so really it won't clear even though it's a new throtle positioning sensor

If you haven't already fixed this issue, this may help.

http://www.automotiveforums.com/vbulletin/showthread.php?t=1112129


I had a very similar issue with my 02 GT. After trying many of the same things you did, turned out to be a bad fuel pressure regulator- guess they are somewhat of a common problem with the Series II.

Was a very simple and quick fix- just need a decent set ring pliers. Part was about 55 bucks at O'Riley.