I just noticed that when I start my car up, the oil pressure is different everytime. I have a '89 LB8 Engine, with stock gauges and sometimes it'll be at the half way point, sometimes it'll be 3/4 up, sometimes 1/4 of the way down...

Well what I've noticed is that when it starts off at 3/4 or VERY close to 80, the car runs and purrrrs verrrrry nicely.... BUT when it's at middle or less than half, acceleration seems a lot slower, and the car literally does not sound as nice...

NOTE that this is at idle(~1700-2000RPM), and not during accel or decel...

My car is completely stock, with just routine maintenance performed...
-Dist. Cap & Rotor, oil + fuel filter, fuel pump, flushed cooling system, air filters

Could it be a vacuum leak?