1. Faulty Ignition Switch: The ignition switch is responsible for sending a signal to the starter solenoid to engage the starter motor. If the ignition switch is faulty or has poor electrical contact, it may cause the starter to engage intermittently.
2. Starter Motor: The starter motor itself could be the culprit. A worn-out or faulty starter motor may not engage properly with the flywheel, resulting in intermittent starting issues.
3. Battery Connections: Loose or corroded battery connections can affect the electrical supply to the starter motor and cause intermittent starting problems. Make sure the battery terminals are clean and properly tightened.
4. Fuel Pump: A failing fuel pump can cause intermittent fuel supply to the engine, resulting in starting problems. If the fuel pump is not delivering sufficient fuel pressure, the engine won't start or may start and stall intermittently.
5. Faulty Crankshaft Position Sensor: The crankshaft position sensor is responsible for providing the engine control unit (ECU) with information about the position and speed of the crankshaft. A faulty crankshaft position sensor may provide inaccurate signals to the ECU, leading to intermittent starting issues.
6. Wiring Harness Issues: Damaged or loose wiring harness connections in the starting circuit can also cause intermittent starting problems. Inspect the wiring harness for any signs of damage or loose connections.
As mentioned, the intermittent nature of the starting problem makes it challenging to diagnose. It's advisable to take the vehicle to a reputable mechanic who has experience working on Toyota vehicles. They should be able to perform further tests and accurately diagnose the root cause of the issue.
