Since it's the sender that provides a variable resistance based on a mechanical pressure, that's where I'd start. For whatever reason maybe the resistor part is somehow shorting or became more resistive, depending on which way those things work. That's my entirely unprofessional first hunch anywho.

97tj, Shaved Ford 9 rear, 4:10's, New 35x12.5 BFG KM2's to test!, Warn x8000i, ARB's, Quick Disco's, Hand Throttle, & it's my DD. smile