my Toyota RAV4 has a check engine light and bad fuel economy what's wrong

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery to ensure safety while working on electrical components.

2. Scan and Address Error Codes

• Use the OBD-II scanner to retrieve error codes.
• Research the codes to determine specific issues (e.g., P0420 for catalytic converter efficiency).
• Clear codes and observe if they return after repairs.

3. Fuel System Inspection

• Fuel Pressure Test:

  • Connect a fuel pressure gauge to the fuel rail.
  • Turn the ignition to the "on" position (do not start) and read the gauge.
  • Compare the reading to manufacturer specifications (usually between 30-50 PSI for RAV4).

• Fuel Injector Cleaning/Replacement:

  • Remove the fuel injectors from the fuel rail.
  • Clean using an ultrasonic cleaner or replace if clogged.

4. Air Filter Replacement

• Locate the air filter housing.
• Remove the cover and replace the air filter with a new one.
• Ensure the housing is secure before closing.

5. Exhaust and Vacuum Leak Inspection

• Exhaust System:

  • Visually inspect for rust, cracks, or loose connections in the exhaust system.
  • Use a smoke test if necessary to find leaks.

• Vacuum Leak:

  • Inspect all vacuum hoses for cracks or disconnections.
  • Use carburetor cleaner to spray around suspected areas; an increase in RPM indicates a leak.