The first thing I would do, and it would cost next to nothing, is run a couple of full tanks of gas through with a good fuel system cleaner just to see if there's any noticeable difference. Secondly, I would change the trans fluid/filter because you've got quite a bit of mileage on it, so you should do that anyway.
Your last post, Randy, reminded me of a '97 Chev S10 I used to own. Whenever I used to drive up the hills north of me, the truck would start 'chugging' and lose power, even if I floored it, and the engine light would come on. It only seemed to do it when the engine was loaded, like going up a hill, but not on level roads. I traded it in before confirming any problem, but I'm sure it was a bad sensor which caused it(fuel/oxygen).
Can you feel anything through the accelerator pedal? does it feel like the engine is faltering or is the engine feeling/sounding consistant while it makes the 'ruffnous'.
