92 rodeo hesitation

I have a 92 rodeo that is idles fine but hesitates once you hit the gas. It bogs down to about 40mph going up any hill and just doesn't seem to be getting enough gas. We habe changed the fuel pump and filter as well as a complete tune-up and it still does the same, the timing is pretty close (sugested in the hanes manual) so we're pretty confident that it's not that. Anyone have any ideas? Much appreciated :-)
-Cat

Sounds like a plugged/clogged cat convertor