1994 trooper oile guage is flucuating with a ticking back and forth motion on the guage and when I come to a stop at a red light It reads zero, I know my oil is full and no leaks so why the ticking i

Bad pressure sending unit?

How long ago did you change the engine oil and what type oil did you put on?

check out the neutral saftey switch on trans, if its reporting unknown gear on scanner while moving t bar it wont know what gear to be in and give you similar problems, also has oil been leaking into switch before?

the PRESSURE guage is just a "for info" guide.when you have an oil pressure problem,you have a red light that will shine brightly at you.........obviously if the guage shows zero you stop, right ?

SOUNDS LIKE THERMASTATE ABOUT TO GO OUT

temperature sender unit top of engine cylinder head make sure its okay
and make sure wire going to it is not grounding
if it grounds or earths it will send the gauge up and down

Try this YouTube video: https://www.youtube.com/watch?v=WRmBdgAViuI Not sure, but hope this helps.

it is normal for you oil pressure to to rise and fall
base on how you are driving ,if your sitting at idle your pressure will be lower that if you driving at 50 or 60 mph.

try another earth cable ?? straight to engine and chassis

There could be several reasons for the problem. The first is the plug is off the sensor, thus no reading. Second the sensor itself has gone bad. Buy a new one and replace it, they are not too expensive. The guage in the dash has gone bad (big pain, buy aftermarket unit and install) and forth the ECM has decided to go bad on that particular guage (very expensive to replace). Have a shop put a trouble code reader on the truck and see what it says the problem is and go from there. You can check the wire to the sensor yourself. Also follow the wiring back from the sensor and make sure there isn't another plug that is not all the way plugged in. A lot of times when the vehicle is worked on and a plug is disconnected and put back together one of the pins in the plug will slide back and not go into the plug, thus causing a problem. So look for that also. Good Luck, RAC