I need some fuel sending unit experts please

I need some fuel sending unit experts please

Sorry, but you misunderstand the circuits so are barking up wrong trees.

bacchustn said
My temperature gauge works perfectly

Then the IVR is working.

bacchustn said
My fuel gauge and oil pressure gauge shows zero reading.

OK. Lets keep that in mind and see what they may share.
(Check the oil pressure gage conenctor and be sure its not grounding somehow)

bacchustn said
I have the type of IVR that attaches to the fuel gauge only

Rally dash. Goes along with having oil pressure gage.

bacchustn said
ith Key on, I am getting fluctuating voltage at the sending unit connector but it varies by timing and voltage.

That's how the IVR works. It provides an average voltage of roughly 5 V by the bimetal contact opening and then cooling and reconnecting.
video showing the pulsing on an analog meter while bench testing

bacchustn said
When grounding out fuel sending unit connector, the fuel needle at instrument panel goes to full.

Please don't do that for more than the briefest period of time! That will burn out the gage.
Put a 10 to 12 ohm resistor on it between the connecting wire and ground. That will simulate a full tank.