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2002 Chevy Impala P0101 Code: Random Stalling, Idle Issues, and MAF Sensor Troubleshooting

Model: Chevy Impala Fault Code: P0101 Posted: 2011-12-09 11:21

Hi everyone, I'm looking for help with a persistent issue on my 2002 Chevrolet Impala with a 3.4L engine. The car randomly stalls when idling, especially after sitting for several minutes—sometimes as little as 5, other times up to 10. This is accompanied by a recurring OBD2 fault code P0101 (Mass Airflow Sensor Circuit Range/Performance Problem). I've already replaced the mass air flow (MAF) sensor with both a used and a brand-new unit—neither has resolved the issue. After a full tune-up including new spark plugs, wires, and ignition components, the problem persists. The behavior is inconsistent: when the P0101 code is active, the car barely runs or stalls immediately upon starting. If I give it a bit of throttle to start, it may run briefly but will misfire. However, if I clear the code while the engine is running, the idle smooths out instantly and the vehicle drives normally. Another pattern: after driving on highways for an extended period, the car tends to stall as soon as I begin slowing down or reach a stop. This suggests a possible issue with idle stability under load transition. I'm wondering if there could be underlying causes beyond the MAF sensor—such as a sticking EGR valve, vacuum leaks, or faulty wiring to the MAF sensor. The smell of burnt catalytic converter sometimes appears when I hold the throttle down during stalling, but disappears immediately after clearing the code. This makes me suspect a possible downstream issue. Any insights or suggestions on how to diagnose and fix this P0101-related stalling in a 2002 Chevy Impala would be greatly appreciated.

Related fault codes
P0101
Comments (4)
Anonymous 2011-12-09 20:06

A sticking EGR valve or vacuum leak can trigger a P0101 code. Be sure to inspect the EGR pintle and check for any vacuum hoses that may be disconnected, cracked, or leaking—these are common culprits in older Impalas with 3.4L engines.

Anonymous 2011-12-11 18:38

I've noticed a strong catalytic converter smell when holding the throttle during stalling—similar to burning—only when the P0101 code is active. The odor vanishes immediately after clearing the code. This could indicate that the MAF sensor is sending incorrect airflow data, causing the engine control unit (ECU) to misfire and overheat the catalytic converter. It's worth investigating whether the issue stems from faulty sensor readings rather than a mechanical failure.

Anonymous 2011-12-12 06:29

Have you tried checking the MAF sensor circuit connections or grounding? A bad MAF can cause misfires and affect downstream components like the catalytic converter. Even if the sensor is replaced, poor wiring or signal interference might still be present.

Anonymous 2013-07-15 08:22

I have the same issue on my 2002 Chevy Impala—clearing the P0101 code makes it start and run fine for a while, but after about 40 miles, the problem returns. I replaced both the MAF and MAP sensors with new units; no improvement yet. Anyone else have success diagnosing this? Could it be related to EGR or vacuum system issues?