I have a situation where my fuel gauge and sender bench test perfectly. Then, in the truck the fuel gauge works great until I start the truck. Then it gets Parkinson's and jumps around, often up behind the F, but will sometimes settle at just the right RPM. This is a 12 volt conversion '53. I have had the alternator tested, and replaced the coil resistor, and added a ground at the tank. All gauge lights work good, so I'm assuming the cluster ground is adequate.
Suggestions?
