How to test TPS Nissan Z32 90-95 style

haveing some voltage issues with my tps. ill set it to the required voltage which is between .42 and.44 volts on closed throttle (so .43 is what i go for), however after a period of time the tps will adjust this base setting on me. screw are snug and arent stripped so i know the tps is staying where i set it but yet the voltage creeps around on me.
bad tps??
what do you guys think?
tps is throttle position sensor for anyone who dosent know.

[@Z32orDIe]

sadly my battery was fully charged at 13.2 volts. it turned out to be a faulty tps. ive since replaced and set new tps with 0 issues.
tps is now set to .43 volts at idle.

[@kimrajramnarine7558]

maybe you battery is dying