oil pressure gauge jumps

[waxman]

i have an 88 lx 2.3 l and when its get hot,at idle the gauge jumps,goes to 0 .rev it up it goes back to normal. is the sender bad,or other problems? thanks

 

[7991LXnSHO]

The only engine I had do that on was worn enough the oil pressure was really low when at idle and warm. It did not do that after a rebuild.
I’m sure there are diagnostic steps for if you doubt the gauge. But I’d first verify the readings with a mechanical gauge before doing anything else.