1992 chevy blazer oil pressure guage

my 92 s-10 blazer 4.3l throttle body has the check engine light on and the oil pressure guage is reading low (at the lowest point on the guage). the oil level is at the full mark on the dipstick. as i am driving and accelerating the pressure rises slightly and the light flickers on and off.(check engine light) there is no difference in the performance of the motor and the gas mileage seems to be the same. could this reading on the guage be a problem with the pump, oil sending unit, oil pressure switch and how can I properly diagnose the problem myself? and should the vehicle still be driven before diagnosis? thank you in advance for your response.