* Dirty or Faulty Idle Air Control (IAC) Valve: The IAC valve regulates the amount of air entering the engine at idle. If it's dirty or malfunctioning, it might allow too much air, causing a high idle. When the engine stalls, the increased airflow might be momentarily too much, leading to a lean condition. Giving it gas increases the fuel supply, counteracting the excessive air.
* Vacuum Leak: A vacuum leak can draw in unmetered air, similar to a faulty IAC valve. This extra air makes the mixture too lean, causing a high idle and potential stalling. Giving the engine gas temporarily enriches the mixture, allowing it to run.
* Faulty Throttle Position Sensor (TPS): The TPS tells the engine control unit (ECU) the throttle position. A faulty TPS can send incorrect signals, leading to erratic idle behavior and stalling.
* Dirty Throttle Body: A dirty throttle body can restrict airflow, causing similar problems as a vacuum leak or faulty IAC valve. Cleaning the throttle body is often a simple and effective fix.
* Failing Mass Airflow Sensor (MAF Sensor): The MAF sensor measures the amount of air entering the engine. A faulty MAF sensor can provide inaccurate readings, causing the engine to run rich or lean, leading to high idle and stalling.
* Problems with the Engine Control Unit (ECU): While less common, a malfunctioning ECU could be causing the issue. This would require a diagnostic scan by a mechanic.
Troubleshooting Steps:
1. Check for obvious vacuum leaks: Inspect all vacuum hoses and connections for cracks, holes, or loose fittings. Listen for hissing sounds near the intake manifold.
2. Clean the throttle body: This is a relatively easy DIY task and often solves idle problems. Use throttle body cleaner and follow the instructions carefully.
3. Check the IAC valve: Inspect it for cleanliness and proper operation (this usually requires some diagnostic tools or knowledge of your specific vehicle).
4. Have a mechanic perform a diagnostic scan: This will check for error codes stored in the ECU, which can pinpoint the most likely problem.
It's important to have a professional mechanic diagnose the issue if you're not comfortable working on your vehicle's engine yourself. Ignoring the problem could lead to more significant engine damage.
