My check engine light is going off on my 89 iroc 350. I did an obd scan and it tells me fuel pump voltage too high or too low, as well as the engine is running rich. The light also goes off after it has run for a while if i turn it off and then turn it back on again, it also feels like it is running better. Does anyone have any suggestions on how i can fix this problem?

 

checking the voltage at the pump would be my first start