Recently, my oil pressure gauge started fluctuating up and down. Sometimes going down to zero and staying there. If if rev the engine, it jumps back up, but then goes back down again, other times it will stat at normal. The engine oil level is at the right level, and it it seems to be running normally, no abnormal noises or anything. I have had the oil pressure sensor go bad on my in the past, but it went all the way to 120 and stayed there. Could this be the sensor going bad again, or is it the oil pump?