Loss Of Power At 2000 Rpms

[fogdog101]

I have a 2000 GMC Sierra sl 5 speed. When I take of it gets to about 2000 rpms and feels like a 100mph wind is holding it back. It still goes but the power just drops kind of like a bike with a power band that all the sudden stops working. Every now and then it will be fine but not much at all. I have replced the cats,fuel filter, plugs, wires, and distr cap but nothing there. The truck does have 171000 on it. I really dont know the history on it b/c i bought it with 168000. i think it was used at a place called Fleet Services. Any help would be great. Thanks

[cammiller]

What had happened to the Cat's? If they were broken, shere did the debris go? Also, did you check fuel pressure and clean the mass aif flow sensor?

[fogdog101]

someone took the cats off b4 me and the check engine came on for the O2's. no more check engine lights since then. how do you check the fuel pressure and also sometimes when im riding down the road and push the clutch in then the idle will go oto nothing like almost cutting the truck off but thin acts normal for a couple of weeks.