last night I went for a cuise around town like usual when I have nothing to do, I grabed a coffee and went out the highway, about ten minuter down the road I noticed that my oil pressure would drop and then pick back up a bit when at a steady RPM so I kept notice on it and it eventually droped down to about 10 psi at cruising speed, so I shut off the car(when I first put the engine in the car I had oil pressure issues which caused me to test every thing in the wiring and the guage it self 6000km or so ago) I soon realized that when I restsrted the car it worked again but only for about 5\10 min so thats how I got home in little hops, this morning I put my hand held on and went for a drive with no problems, so I purchased an el'cheapo guage and install kit from canadian tire and hooked it up with no problems for it to show me the same good pressure reading as the hand held.

what could cause the fluxuation in the stock guage? any sugestions on why this could happen,
sorry bout the run-on story and thanks for any helpI'll be back in a few hours

 

probably being 20 years old will do it, but a poor connection on your pressure sender (under the oil pedistal) would give you some off and on readings. https://www.rx7club.com/1st-generation-specific-1979-1985-18/oil-pressure-guage-580779/ this post shows a pic, it's the "mushroom" as trochoid so elegantly called it.

 

Yeah, clean the connector and if that doesn't improve it, get a new one. Some prefer an aftermarket for accuracy. Your choice.

 

he already checked the wires, and installed a new gauge, did you guys even read his post?

 

front cover O-ring. Replace that and while you're at it, mod your ROPR.

 

We did, did you?

1. He checked the wiring 6000 kms ago, and it's not clear if he checked it at the pressure sender unit end, or at the gauge end.

2. We're talking about replacing the unit sender, not the gauge.