davek9

You could also remove the sender and the assembly (a By-pass w/ spring) that screws into the block and clean it. I've found gunk in ones that I have cleaned.

blazing928

my temp guage did the same, the guage was faulty, so also the pod elec contacts could be the prob, but my GUESS is the guage

Maleficio

I installed a voltage stabilizer that calmed down my dancing volt gauge, but it didn't cure my dancing oil pressure gauge at idle. Obviously it's purely electrical, and I would guess excess resistance in the circuit that impedes the signal at the lowest level causing bouncing needle.