The tps is really easy to check with a logger, especially in the graphing mode.
When you are checking it with an ohmeter, it's unloaded, and may check just fine, especially with a digital meter, because the numbers hop around so much it's hard to see the trend. (An old school simpson analog meter works well, but they're just about as extinct as people who know how to use them. /ubbthreads/images/graemlins/rofl.gif)
Trust me, use a logger!!!
The key is to watch for drop outs.
The *actual* voltage it's reading isn't quite so critical, only that it is consistent, and increases linearly when you sweep the throttle. The range should be ~.5v closed to ~5v wide open (exact spec is .48v to .52v at idle, with the throttle closed)
I've seen them waaaay out of range, and the ecu will just compensate with the fuel trims, so don't freak if you're a little out of spec. (But you will know, and so will the the automotive gods, so it's best to get it spot on... /ubbthreads/images/graemlins/smile.gif)
*Usually* they fail where they operate the most, right around 1/16th to an 1/8th throttle, and they will drop off fairly consistently when they are warm. You can also gently tap the tps housing and watch for spikes/drop outs to simulate vibration, but it's generally not necessary.
Give the harness a bit of a wiggle where it plugs in as well, as corrosion on the pins of the connector will give the same symptoms as a bad tps. A simple cleaning of the male pins with some rubbing alcohol on a q-tip, and then plugging/unplugging things a few times will go along way towards eliminating that possibility.
On a freshly rebuilt t-body, set the tps in the center of it's range of adjustment. Just eyeball the gaps on both sides of the mounting screws.
Make sure the closed idle switch is adjusted correctly (somebody got the vfaq link? my computer is acting up today... /ubbthreads/images/graemlins/banghead.gif)
Set the base idle correctly, (to insure the closed idleswitch and t-cable are correctly adjusted) then reset the tps to read .5v, and you're done!
I have a known good loaner tps if you need one.