* Idle Air Control (IAC) Valve: This valve regulates the amount of air entering the engine at idle. A dirty or faulty IAC valve can cause the engine to stall, especially when idling or under low engine load (like when turning).
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the engine's computer the position of the crankshaft. A faulty CKP sensor can cause erratic engine behavior, misfires, and stalling. This is a common cause of stalling issues.
* Throttle Position Sensor (TPS): The TPS tells the computer the throttle's position. A faulty TPS can lead to incorrect fuel delivery, causing stalling, especially at low speeds.
* Mass Airflow Sensor (MAF Sensor): This sensor measures the amount of air entering the engine. A dirty or faulty MAF sensor can cause the engine to receive incorrect fuel mixture, leading to stalling.
* Fuel Pump or Fuel Filter: A weak fuel pump or a clogged fuel filter can restrict fuel flow, especially when the engine is under low load. This can cause stalling, particularly when idling or slowing down.
* Vacuum Leaks: Leaks in the vacuum system can disrupt the engine's performance, leading to stalling.
* Ignition System Problems: Worn spark plugs, faulty ignition wires, or a failing ignition coil can also cause the engine to die, especially under stress.
* Alternator: A failing alternator may not be charging the battery sufficiently. If the battery is low, the engine can stall.
Troubleshooting Steps (Do these in order, as some are simpler and safer than others):
1. Check the battery and charging system: Make sure the battery terminals are clean and tight. Have the alternator and battery tested at an auto parts store. A weak battery can cause stalling.
2. Check for vacuum leaks: Visually inspect all vacuum hoses for cracks or loose connections.
3. Clean the MAF and IAC sensors: These sensors are sensitive and can be fouled with dirt or oil. Carefully clean them with MAF sensor cleaner (available at auto parts stores). Do not use anything other than MAF cleaner on the MAF sensor!
4. Check the fuel filter: If it's visibly dirty or hasn't been changed in a while, replace it.
If you're not comfortable doing these checks yourself, take your Buick Regal to a qualified mechanic. They can properly diagnose the problem and repair it safely. Describing the exact circumstances of the stalling (e.g., "it stalls only when turning left at a slow speed," etc.) will help the mechanic pinpoint the cause.
