hesitation

i have an 89 toyota celica ST. after toyota forgot to tighten the screw to the oil pump gear during a timing belt change, I got a free shortblock replacement. ever since i got the car back, it hesitates from a stop. i can also feel the car accelerate in spurts instead of smoothly. the car seems to do fine as the rpm's climb so i don't think it's the fuel filter. the air filter is clean, the idle and timing is adjusted within spec. the only diagnostic code i get is the a/c switch, but i already knew that. i also cleaned the throttle plate area with some carburator cleaner. does anyone know of anything else i could check?

There could be moisture in the distributor cap. Or the could be a problem with the vaccum system like a vacuum leak, but without feeling it myself, it is hard to tell. Oh yeah, maybe a bad TPS???