Separate MAF rationality from low/high-frequency circuit faults before replacing the sensor.
P0101 is a rationality test: the PCM compares measured airflow with its speed-density calculation. P0102 and P0103 are low- and high-frequency circuit faults. Treating all three as “bad MAF” skips the diagnostic architecture.
GM's 1998 LS1 diagnostic parameters define P0101 as excessive disagreement between measured and calculated airflow, while P0102/P0103 identify frequency outside the calibrated circuit range.
GM later released a 1998 F-car bulletin for P0103 under certain wide-open-throttle upshift conditions. If strategy-based diagnosis finds no vehicle fault, calibration identification belongs in the branch before condemning hardware.
Aftermarket MAF housings, cold-air systems, relocated sensors and calibration changes can invalidate stock airflow assumptions. Diagnose the hardware and calibration actually installed.
Use the proven failed branch—not the original symptom—to choose the replacement. Go from diagnosis to the Parts Verdict →