1996 Chevy Astro 2WD P0102 Code: MAF Low Input - Persistent After Sensor Replacement
I own a 1996 Chevrolet Astro Van with a 2WD configuration and am currently experiencing trouble code P0102 (Mass Airflow Sensor - Low Signal). I've already replaced the MAF sensor, inspected and repaired all wiring connections, installed a new throttle position sensor, and cleaned the throttle body. The code clears immediately after these steps but returns within seconds. The vehicle starts normally, stumbles slightly during operation, then recovers—however, it does not stall under normal driving conditions. It only stalls when shifting into reverse, and resumes running afterward without issues. This behavior suggests a potential sensor or system-level issue despite the MAF replacement. I'm seeking advice on possible root causes beyond the MAF itself, such as exhaust restrictions, vacuum leaks, intake snorkel damage, or electrical signal interference.
The only other component I can think of replacing is the Powertrain Control Module (PCM)—though it's rare. Given that this 1996 Astro Van has accumulated 277,000 miles, a failing PCM could be a plausible explanation despite low probability.