My brother just bought it as a beater until he gets back up on his feet. It's got 120,000 miles on it and has never had a tune-up and the SES light has been on forever. Well, he was driving it around and he said it's been hesitating when going up hills and various driving speeds on the hwy. I had the same problem with my mom's van, changed the plugs/wires, fixed it everything. Runs great.
Well, today it started running real rough and finally just died and won't crank back up. I'm 99.99% sure it's the wires/plugs. What do ya'll think? It's getting air and fuel. We're gonna tow it up to the auto parts store and see what codes it's throwing also.

 

We have a 2001 Grand Prix GT with 49,000 miles. Over time the performance started dropping off to the point where it couldn't get out of it's own way. Then it didn't like to rev above 4000 rpm and wouldn't shift from 1st to second under hard acceleration. Then it started with random SES lights, until it finally stayed on for good. The only code we got out of it was "Random misfires". The solution was replace the cat, as it was plugged up pretty good.

 

Our '99 GTP was acting similar a couple years ago. I don't think it ever died on us or threw a SES, but it would hesitate occasionally and the instrument cluster would go dead for a few seconds then come right back. The Crankshaft Position Sensor was the culprit, common problem on the 3.8 supercharged engines, don't know about the 3.4 or 3.8 NA engines. There is also a fuel resistor that blows and can kill the car, but you said you are getting fuel so it's probably OK. Check it out anyway:
http://www.clubgp.com/cgi-asp/mods.asp?modid=9

Might ask here too: http://www.clubgp.com/

 

I had a 00 GTP. Fuel pumps are known for going bad as well. Check that resistor like already mentioned.

Plug wires are a common problem. Coil packs, mainly #4 I think it is.

If you need any parts let me know and I can put you in touch with a guy who sells used parts and good prices.

Also, check out the website he gave you.

 

Grand Prix Is Very Common For Fuel Pump/ Wire/plug..... Also Fuel Filter... Some People Forget They Are There... And It Could Be As Simple As That...

You Mey Be Getting Fuel..... But Are You Getting Enough??

 

Check the codes and go from there.....at this point you are throwing a dart at a board and hoping for a bullseye.

 

HAHA OH SO TRUE

THANKS ALOT FOR RAINING ON OUR DIAGNOSIS PARADE THERE BRIAN

 

ehhh, just trying to save the guy some work! If I could diagnose cars from home, I would never get outta bed.

 

AHA JFWY BRIAN

 

I know....don't let my "internet" voice make it sound any different.....LOL