1. Idle Air Control (IAC) valve is dirty or faulty. The IAC valve is responsible for controlling the amount of air that bypasses the throttle body at idle. When it's dirty or faulty, it can cause your car to idle too low or stall when you put it in gear.
2. Throttle body is dirty or blocked. The throttle body is responsible for controlling the amount of air that flows into the engine. When it's dirty or blocked, it can restrict airflow and cause your car to idle too low or stall when you put it in gear.
3. Vacuum leak. A vacuum leak can also cause your car to idle too low or stall when you put it in gear. This is because the engine is not getting enough air to operate properly.
4. Transmission problems. If your transmission is not shifting properly, it can also cause your car to idle too low or stall when you put it in gear.
If you are experiencing this issue, it is important to have your car diagnosed by a qualified mechanic to determine the exact cause and have it repaired.
