Help! TPS volts reading opposite?

So I'm trying to rectify the common idle drop issues and have found many helpful threads here. I have checked for vacuum leaks, replaced the IAC. The IAC has helped some but the idle drops below 500rpm occasionally. Usually when coming to a sudden stop. It has not died out.

I went to back probe the TPS using a good Fluke DVM. For some reason I read 4.039vdc at closed throttle and .370vdc at wide open. Almost opposite of normal.

What gives? Is it time to just replace it? I got a quote for only $25 but don't want to waste any cash.

Thank you in advance for any response.

Thanks I'll give it a shot. Previous owner put a BBK 70mm TB on it. Hopefully the throttle set screw has not been messed with. I'll be surprised if the TPS is that far out of adjustment. The Haynes manual states the TPS is not adjustable contrary to forum and other tech articles online.

I will post results. Thanks!