Z28harcor

So I bought a used lingenfelter throttle body. Little did I know it was for a tpi. So I bought the pigtail for a tpi tps and cut mine and spliced it in. The wire colors matched. I'm trying to adjust it. I'm getting the 5v from the PCM (gray wire)and I'm getting 4.6 volts back outta the tps at idle( blue wire)And when I open the throttle the volts go down.. It's reading it backwords or something any help would be great. It's the flat blade style connector I bought off eBay. Has grey wire on top then blue in middle and black on bottom ...so basically blue and grey wires are at same voltage with butterfly's closed open them and the volts go down on blue wire !!