TPS problem.....really confused

Got a 99 GT with a aftermarket plenum and a bbk 75mm TB. i messed with the throttle stop screw to get the bind out when i first installed it. the TPS that came with the TB went bad, so i contacted bbk to make sure stock TPS would work for a replacement. Of corse it did, but ever seince i've had odd issues with throttle smoothness, fuel mileage, and (from how it smells) improper fuel delivery (rich and lean) before and at WOT. I got the volt meter out and started checkin stuff and here's what i got; Closed: Ref= 4.2 volts Sig=4.2 volts. As i open it: Sig drops down to .20 volts instead of goin up. So my question is, is it the TPS bad or PCM messed up. I don't usually get stuck, but im highly confused and could use some guidance. Thanks in advance!

I screwed up. They changed the wire colors from 96 to 99 and i was measuring everything backwards. I went and looked at my schematics rite after i posted this and seen the wire color differences to the TPS. I had to slightly modify the TPS (i found my spare so i didn't mind) to make it adjustable. its sitting right at .52V at idle, but when i kick the throttle all the way open, my TPS only reads 4.60V instead of the around 5V its supposed to. I played around with it and could get the WOT up to about 4.8V, but when i did that, it put my closed volts at 1.2 which is too high. So i put it back to where i had it first and i got smoother accel, and no rich or lean smell at WOT. A buddy told me that the 4.6L cars were non adjustable cause the EEC 5 can take up the slack that the EEC 4 can't. Any truth to that? And is my computer reading WOT even tho my TPS volts at WOT is 4.6?