Oil Gauge Not Working

I got my oil changed about three months and after about a month my oil gauge started dancing around. I checked my oil and it was fine. I just got it changed again thinking maybe it was something the last place did, but it's still just sitting on empty and then it will bounce up to a normal level for a while and then go down to either empty or a quarter full. It doesn't seem to be affecting my my vehicle (90 4runner) but it makes me nervous seeing my oil gauge moving around or on empty line all the time. Any ideas what the problem could be?

but it's still just sitting on empty and then it will bounce up to a normal level for a while and then go down to either empty or a quarter full..........oil gauge moving around or on empty line all the time.

First of all it is a pressure gauge not a full or empty gauge.

So standard advice for EVERTHING automotive: "If it worked until you fixed it, then check very closely around what was done".

That being said this sounds like an intermittent electrical wiring problem, there is a transducer just above the oil filter (V6) that has a push on connector. It looks like a little can screwed in to the side of the block with an electrical stud in the middle. Check there first.

could be wiring and could be pressure sending switch along with a fualty oil pump

The reason I suggest it is the sending unit or connector at teh sending unit is because it was fine BEFORE the oil change.