my Toyota Highlander Third Generation (2014-2019) won't accelerate past 40 mph, what's wrong

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is on a flat surface and the engine is off for safety.
• Disconnect the battery to prevent electrical shorts.

2. Throttle Position Sensor (TPS) Inspection

• Locate the TPS on the throttle body.
• Disconnect the electrical connector from the TPS.
• Use a multimeter to test the TPS; it should show a varying voltage as the throttle is opened and closed.
• If faulty, replace the TPS with a new one.

3. Mass Airflow Sensor (MAF) Cleaning/Replacement

• Locate the MAF sensor on the air intake duct.
• Disconnect the electrical connector and remove the MAF sensor.
• Clean the MAF sensor using MAF cleaner or if damaged, replace it with a new sensor.
• Reinstall the MAF sensor and reconnect the electrical connector.

4. Fuel System Inspection

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position to check for proper fuel pressure (should be within manufacturer specifications).
• If pressure is low, check the fuel pump, filter, and injectors for blockages or failures.
• Replace any faulty components as necessary.

5. Exhaust System Inspection

• Inspect the exhaust system visually for any signs of damage or blockage.
• Check the catalytic converter for any signs of clogging (e.g., overheating or rattling noises).
• If the catalytic converter is found to be blocked, replace it.