Help: TPS reading is getting weird
 

After installing VTPS in my Miata, the TPS Calibration for 0% ADC is 294 and 100% ADC is 2896 and that was 6 months ago.
Last week, my car start stumbling on cruise and i found that that mysteriously, the TPS is only reading 50% when I full throttle. So i readjusted the TPS and last week the TPS Calibration for 0% ADC is 156 and 100% is 1398.
Just today, my car started stumbling again, and i found that my tps is reading 50% again!!!. So i readjusted again, and the TPS Calibration for 0% ADC is 126 and 100% is 630.

Can you tell me where the problem is likely to be? The TPS or the adaptronic output?

Is it loose?

Thats what i thought initially. I checked, No it was not loose.

bad wiring in tps or bad solder joints?

Still getting 5v

i figured its the TPS, i am getting 5v at the connector and 0.2v on close throttle and 1v at full throttle.
Waiting for my BMW tps to arrive in Singapore and its taking agesssssss

probably the case, if at WOT you're only getting 1v to the output that's the issue.

Guys, would anyone know if the NB tps would fit the 1990 NA?

just in case someone has the same problem. Yes, changing the TPS solves my problem.