1995 Oldsmobile Cutlass Stuttering/missing while driving

My 95 Cutlass Supreme has been "stuttering" while driving for quite some time. It seems that when I require a little more power (like going up a hill) the engine kind of misses a beat and stutters a bit. The tach bounces around from like 2500 to 2800 during this time. Sometimes it just does it while driving on level ground, and sometimes it doesn't do it at all. Any suggestions?

In the past two years it's had the headgasket replaced, the transmission rebuilt, new plugs and wires, fuel filter, ball joints, water pump, alternator, battery, and a few other odds and ends I probably forgot.