After you reset the tvs cable, does it still not go over 3.8v on the tps?
The only reasons to have it higher are so you can program the chip and to turn the ac compressor off at 4.1 volts if Eric leaves that in the chip.
Having said that, it should be easy to get into the 4v+ range. Have some one mash the gas pedal to the floor while you are watching under the hood....while pedal is on the floor, look at the throttle lever on the throttlebody and see if it is against the stop or not...if it is not, grab it with your hand and see if you can pull it the rest of the way open...if you can, then you need to stick the tie wrap under the pedal under the ball on the end of the cable to take the slack out.
It it was open all the way, you need to readjust the tps...grab it and move it all the way forward so that both slots are up against the screws and then rotate the top back while keeping the bottom slot against the screw until you get the desired voltage. That should give you max wot voltage.
Or, just go by what I wrote on my site.