P0101 Fault Code on 1996 GMC Yukon 5.7L Vortec Blower System - Diagnosis and Fix
Hello everyone, I'm currently troubleshooting a P0101 malfunction indicator code on my 1996 GMC Yukon with the 5.7L Vortec engine equipped with a V-2 trim blower system for towing purposes. The original blower kit included an additional fuel pump, regulator, and a Code 103 buster (adjustable frequency modulator). Initially, the setup performed well—running smoothly and handling over 1,000 miles of towing without issues. Suddenly, the engine began running rough with excessive richness, visible black smoke, and fouled spark plugs. A P0101 code appeared in the diagnostic system. After reviewing the kit instructions, I discovered that the Code 103 buster is only required if boost pressure exceeds 6 psi—something unlikely during low-RPM towing conditions. I recently disconnected both the Code 103 buster and the extra fuel pump to eliminate potential interference. The engine now runs significantly smoother, but the P0100 code persists. My question: Could this be a failing Mass Airflow (MAF) sensor? Or is the additional airflow from the blower disrupting MAF readings? Any experienced users with Vortec blower installations on 5.7L GMC trucks who have encountered similar P0101 issues? Please share your insights or troubleshooting steps. Thanks in advance for your help!
For reference, I found that a dirty MAF sensor was the root cause. After cleaning it with ether, the P0101 code cleared and engine performance improved significantly.