1999 Chevy Silverado P0101, P0137, P0157, P0300 Troubleshooting - Engine Stalls & Loss of Power
Hi everyone! I'm looking for help with my 1999 Chevrolet Silverado 5.3L fuel-injected, automatic, 2-wheel-drive truck (130,000 miles). The vehicle occasionally stalls during morning drives to work and experiences severe power loss when driven home after lunch—only managing about 20 mph before the engine begins to lose responsiveness. After roughly half a mile, it gradually regains speed, but when shifting gears, I hear a backfiring sound coming from inside the engine, which sounds like a carburetor issue—but my truck doesn't have one. The check engine light is on and displays codes P0101, P0137, P0157, and P0300. I previously replaced the oxygen sensor located behind the catalytic converter with no improvement. A mechanic mentioned that code P0101 might relate to the Mass Air Flow (MAF) sensor located above the air filter—specifically referring to the expensive $153.99 MAF sensor. I'm hesitant to purchase it without confirming it's actually the root cause. Any insights or suggestions on how to diagnose and fix these issues? Thanks in advance!
Do you have a K&N air filter installed? Oil buildup from such filters can contaminate the Mass Air Flow (MAF) sensor. Inspect the MAF sensor for contamination. Consider cleaning it using brake cleaner or electrical cleaner—spray directly into the sensor's internal wiring, let it dry for several minutes, then reconnect. After cleaning, check for any air leaks downstream of the MAF sensor. Additionally, has a tune-up been performed? Use a digital volt-ohmmeter (DVOM) to test the circuit connected to the oxygen sensor behind the catalytic converter. Ensure the connector is intact and that no pins are bent or loose.