I got a 1998 Buick park avenue 3800 series 2 and i put new head gasket and new intake and i got it code P0300 is Random misfire and P0102 mass air flow circuit low voltage and it runs real Rough it got 250,050 miles on it

check the wiring from the maf sensor to the computer and replace the sensor if the wiring and computer checks out ok

that what causing the misfire due the Mass flow sensor problem