Mine did the same exact thing. Check your fuel pressure. My dad and i checked it and it was at 7, depending on who you talk to TBI is suppose to run between 10-13/15. So we ran up to O'Reilly's and got a kit thing to rebuild the fuel pressure regulator. Runs like a raped ape now!!
I also have another question... Do any of you know where I can get replacement trim for my interior? It's that aluminum strip that goes across the dash and along the door panels. It also has the assistance straps. I've looked every where but I can't seem to find the stuff I need.
I have done some digging(first page of google seach) and have come up with what i think i'll try...
http://gbodyforum.com/viewtopic.php?f=16&t=36209#.UhpNfz84L-I
There are some holes in the roof where the head liner was. The previous owner put an interior in it from a Suburban, hence why it has four window switches but only two windows.
There is no headliner in my truck, the dash pad has some big cracks in it, and the dash on top of the speakers has peeled up and chips away when you touch it.