2000 5.2L 2wd SLT oil press gage

[Lord_of_Mice]

Ok y'all I have slightly new angle on what looks to be an issue others have had.

Just bought a 2WD 2000 Durango SLT with a 5.2L w/ 140K miles.
I don't believe I have an engine issue so much as an indicating issue.
Problem is that the oil pressure gauge reads a solid, non wavering pressure of just under the 40 increment above idle. Stopping at a light, engine goes to idle and the gauge flat just drops to nothing....check gauges light comes on...chimes a couple times. This gauge either reads one or the other, just under 40 or zero, nothing else.
A little background: oil changed, used Mobil1 syn, I have serviced the rear diff, tranny & filter followed by a tranny fluid flush, new thermostat and coolant flush, power steering and brake fluid flush. New cap rotor & plugs, new oil press sending unit, and I have replaced the instrument cluster due to a speedometer issue. (I did change both the diff and output VSS sensors with no luck on the speedo issue)(cluster fixed speedo).
The oil press gauge did the same thing with the first instr cluster.
oh, the the cluster I put in was used.....but seems odd to have the same exact problem.
Note that when the oil pressure indication drops to zero, there is no lifter noise, nothing.

[Lord_of_Mice]

Has anybody seen something like this before?

I really would like some options before yanking the engine.

If more info is needed, please let me know

[jpb53]

You need to put a manual gauge on it and see what you actually have before you go too far.

[Lord_of_Mice]

I think that's a good suggestion. I guess I'll take out the electric one and put in a mechanical one.

or maybe you/somebody can tell me where another port i can tap into might be....then i could compare the two.

thx for the idea