Oldsmobile/Buick Repair: performance, fuel pump relay, buick regal

Question
I have a 1996 Buick regal, 3.1L w/ automatic trans and about 190,000 miles on it. Just recently, my car has started to run badly, but sporadically. When I say run bad, at times while driving 50-60 mph, the idle will fluctuate wildly and the car will then stall. Once the car stops, I can start it and the idle while in park is normal, but once I begin to move, the fluctuation starts again. After it sits for say 1-2 hrs, it seems to run fine. I took it to a mechanic and after he drove it for about an hour, the problem did not occur again. All systems checked out okay. The next day, after I drove for about 1/2 hr, the problem came back.

Not sure what to do.

Answer
hi charles.well the prob sounds like a fuel pump or even possibly a fuel pump relay.and if you have not changed the filter in awhile you should definately do that.a pump gets weak it will heat up and kick off.until you turn key off then on relay will not restart it.and the reason it ran fine for your mech is .two diff types of driveing.try and explain to him the way you drive and the amount of stopping and going again you do..good luck please don,t forget to rate my service ty billymac