Change the fuel filter first. The next possibility is your distributer being worn out. On high mileage tbi engines the bushing in the distributor wear out and the shaft moves around just enough to cause an eradic pick up signal from the coil pick up in the distributor. This causes all kind of unexplained down power and misfires. I have heard of it before then 6 months ago my brother's 93 tbi truck actually had it happen to his.

 

Alright, I'm gunna replace the fuel filter, and the o2 sensors and go from there. If she still does it then I'll look into the distributor and see if that helps. Thanks guys