Jack,
Using the CR's tank and sending unit I assume?
Pretend someone else told you this.
Drop the tank, pull the sending unit out. Take some alcohol, the wood type and clean the resistor. (Petek - right terminology?). Pulling the sending unit out AND putting it back in can be a little tricky. I suspect that the float arm could have been bent a little when it was installed. This would indicate the sticking needle problem, a dirty resistor indicates erroneous readings.
DV -- now I'm back to my corner