My 00 cav. will hesitate after I shift into another gear, but only if I throttle heavy. If I shift, then feather the gas pedal there is no bucking. I think its an emmision system problem, any ideas?

 

This is tough without seeing it. If we first weed out that you're not as bad as I am with a clutch! there's no code set and you've stayed on top of the usual routine maintenance stuff. then it could just be some dirt/gum build-up somewhere..i.e. air filter, fuel filter, throttle body, plugs, vacuum leak, etc. start with the cheapest and easiest to check first.
What in the emmision system are you thinking it could be?

 

Its not the clutch. I replaced the plugs, wires, air cleaner, & fuel filter 2 years ago, so they are pretty new! I was thinking it could be a pvc valve prob. but i dont think my 00 has one. Then i thought it could be a vaccuum leak, but just not sure. No check engine light either!