1. Fuel pump issue: The fuel pump inside the fuel tank may be faulty. This can cause a lack of fuel getting into the engine, leading to the stalling.
2. Clogged fuel filter: A clogged fuel filter can restrict fuel flow to the engine.
3. Fuel pressure regulator failure: The fuel pressure regulator maintains a consistent fuel pressure in the fuel system, and if it is damaged, it can cause the engine to run or crank and then stall.
4. Faulty ignition switch: If the ignition switch fails to supply proper power to the ignition system, it can lead to the engine shutting off.
5. Malfunctioning Idle Air Control (IAC) valve: The IAC regulates the air entering the engine during idle, and a malfunctioning IAC valve can disrupt normal engine idle.
6. Vacuum leaks: A vacuum leak in the intake system could lead to a lean air/fuel mixture, causing engine starvation.
Recommended steps to troubleshoot and resolve the issue:
1. Verify fuel delivery: Check that fuel is reaching the engine by disconnecting a fuel line and verifying fuel flow when the ignition switch is turned to the "ON" position.
2. Check fuel pressure: Connect a fuel pressure gauge to the fuel rail to ensure it is supplying the specified fuel pressure as per Toyota specifications.
3. Replace fuel filter if necessary: If the fuel filter is dirty, replace it to ensure adequate fuel flow.
4. Inspect for vacuum leaks: Visually inspect the intake system for any disconnected or damaged hoses that may be causing a vacuum leak.
5. Check ignition switch: Test the ignition switch by turning the key and observing if the dashboard lights turn on and the starter engages.
6. Clean IAC valve: Clean the IAC valve with an appropriate cleaning solution and inspect its operation to ensure proper idle.
If the problem persists, further diagnosis by a professional mechanic may be necessary as it might require more specialized diagnostics or specific part replacements based on the symptoms and observations made during troubleshooting.
