I have a 2001 Z-28 Automatic, and it seems like every time I get it out and drive around for 30mins-1hour the oil pressure will drop and fluctuate constantly when I stop at stop lights, even when it fluctuates as soon as I press the gas it's normal again. My Check Engine Light is on but I'm positive it's a bad cat on my driver side cause I had the code read. So I dont believe that has anything to do with it. And the car itself runs fine, it's been doing this for probably six months now. I even raced it at the track when it was fluctuating and it ran a 8.58 with a 273 gear, I was surprised. Any suggestions would be very helpful.