What VISCOSITY are you running ... Mine hates full synthetic at Idle I'll have near ZERO on gauge as soon as I give it gas it shoots to midgauge ..
Synthetic Blend it's mid gauge all the time

 

hey all, thought a bit about this prob. the oil pump is a gerotor (G-RO-TOR) type, gear-rotor. as far as i know they are not adj. that said there are only a few things that can effect the press.

1. clogged oil filter, but ONLY if the eng did not have a high press bypass, which would allow oil to bypass the filter in the event it became clogged (this became common in about 1960).
2. low oil. check it.
3. bad sending unit, cheap to replace.
4. a short between the guage/light, can be checked with a multi-meter.
5. the pumps bearings are on the way out, causing slower than norm pumping action, just a thought.
6. the pick-up tube filter screen is covered in sludge and not allowing enough oil to be sucked up. drop the pan and clean it up.
7. the pump is just worn out and can't make the press it used to.

hope it helps, happy motoring.