Seriously THIS is the 1ST step.
Typical forum answers making you do the hardest thing first like pulling a pan or plumbing a gauge.
Just change the sender and see it it goes away.
If the engine isn't changing tone I bet it is this.
My sending unit with a Guage went bad randomly it did the same thing.
Could also be a loose wire.
Easy first then progressively harder.
Throwing parts at it is not diagnosis and teaches him nothing. The first best suggestion is to get a manual gauge on it. There are procedures for everything and verification of oil pressure.....or lack thereof should be the first thing he does.
