why does my Toyota Highlander Third Generation (2014-2019) engine hesitate when accelerating

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Gather necessary tools and parts.

2. Fuel System Inspection

• Tools Required: Fuel pressure gauge, wrench set.
• Sub-steps:
  1. Locate the fuel rail and connect the fuel pressure gauge.
  2. Turn the ignition to the "ON" position (do not start the engine) to check fuel pressure. It should be within the manufacturer's specified range (typically 50-60 psi).
  3. If pressure is low, check the fuel pump and replace the fuel filter if clogged.

3. Spark Plug Inspection

• Tools Required: Socket set, torque wrench.
• Sub-steps:
  1. Remove the ignition coils or spark plug wires carefully.
  2. Use a spark plug socket to remove the spark plugs.
  3. Inspect each spark plug for wear, carbon buildup, or incorrect gap. Replace with OEM-spec plugs if necessary.
  4. Torque the new spark plugs to the manufacturer’s specifications (usually around 13-15 lb-ft).

4. Air Intake System Check

• Tools Required: Screwdriver set, cleaning brush.
• Sub-steps:
  1. Remove the air intake duct to access the air filter and MAF sensor.
  2. Inspect and replace the air filter if dirty or clogged.
  3. Clean the MAF sensor using a MAF sensor cleaner; do not touch the sensor elements.
  4. Reinstall the air intake duct securely.

5. Throttle Position Sensor (TPS) Testing

• Tools Required: Multimeter.
• Sub-steps:
  1. Locate the TPS on the throttle body.
  2. Disconnect the TPS connector and set the multimeter to measure resistance.
  3. Check the TPS operation by moving the throttle plate; resistance should change smoothly. Replace the TPS if readings are erratic.