Started up the car to cruise to a show yesterday and noticed the gauge (70 Cuda)was reading very low. The gauge fluctuated slowly between half reading and none. I hit the highway thinking that if its going to give way then its now or never. The gauge acted the same and there was no apparent ill effects on the car (No noise, smoke or otherwise) A mechanic at the show suggested it was the oil pressure sending unit and just replace that. I looked at the unit and found that I had replaced that piece during an underhood detail session with a new unit only about a year ago.
So is it the unit, oil pump or something in the gauge?

Check it with a mechanical gauge.Ive never trusted elec gauges>Too much to go wrong.That and just because the sender was new dosent mean its good.Ive heard that line too many times in turning wrenches for almost 30 years.It cant be bad its new.Yeah right.Seen too mant new parts that are bad.That and if the pressure checks good try a new sender they are cheap.Rocky

Did you check the wire to be sure it's snug on the the sender. Those push ons loosen up over time.

And, of course, don't forget our old friend, "the corroded firewall connector."

There is VERY little current in this circuit, so if the firewall / bulkhead connector is corroded/dirty, that will break the gauge connection.

Post deleted by cnxt