I've got a tired 2.8 in a 91 trooper that i've put new injectors, new plugs/wires/cap/rotor, and performance 2.5" collector-back exhaust onto... as i've done this its hesitation from standstill has seemed to get worse.

Automatic transmission, btw.

if I'm already moving, throttle response is fine - but if i come to a complete stop, then step on the gas it kinda sputters and puts out nearly no power for 1 to 2 full seconds, then BAM comes alive and accelerates like it should. Next time I come to a complete stop, the same thing occurs.

Any ideas? timing? IAC motor?

Check your T.P.S. This is easily done with a meter to see if there are any "dead spots" in the TPS's resistance curve.

If it checks out good, do the idle air/TPS Voltage checks/adjustments. If you cycle the throttle from idle to full while monitoring TPS voltage it's another good verification of TPS linearity.

I don't have the link handy at work but do a keyword search on "TPS" or "IAC" and you'll come up with good tips on doing the checks/adjustments. Or check at the www.s-series.org 60 deg V6 forum.

HTH...........ed