I am working on a 1993 F150. The voltage gauge fluctuates while pushing the gas especially right after start up. It is also very erratic when operating the power window switches, it seem like the drivers power window switch makes it jump alot. I am also getting a cel code for low voltage at the TPS. What is causing the voltage fluctuation and is it related to the cel. I have changed the TPS sensor.

 

check ur grounds.i had a ground going from the back of the motor to the firewall and one from the core support under radiator to the engine that was broken and causing low charging indication and the window motor is probably goin bad. Mine is getting to the shot point and it draws way more than thr right