my Honda Pilot YF4 (2023-Present) fuel economy has dropped significantly, what's wrong

Solution

1. Preparation

• Gather tools and materials: OBD-II scanner, fuel pressure gauge, socket set, air filter, spark plugs, torque wrench.
• Ensure the vehicle is parked on a level surface and the engine is turned off.
• Disconnect the battery to prevent electrical issues.

2. Address Diagnostic Trouble Codes

• Connect the OBD-II scanner and retrieve any stored codes.
• Note codes related to fuel system or engine performance (e.g., P0171 for lean condition).
• Clear codes after addressing the root cause to see if they return.

3. Fuel System Inspection

• Check Fuel Pressure:
  • Connect the fuel pressure gauge to the fuel rail.
  • Start the engine and observe the fuel pressure reading; it should match the manufacturer's specified range (consult repair manual).
  • If the pressure is low, consider replacing the fuel pump or checking for clogged filters.

4. Air Filter Replacement

• Remove the engine air filter housing.
• Take out the old air filter and inspect it for dirt and blockages.
• Install a new, clean air filter, ensuring it fits snugly.

5. Spark Plug Inspection and Replacement

• Remove the spark plug wires gently.
• Use a socket wrench to remove each spark plug.
• Inspect for signs of wear or fouling; replace if necessary with OEM spark plugs, torquing to manufacturer specifications (typically around 13-15 ft-lbs).

6. Tire Pressure and Condition Check

• Use a tire pressure gauge to check all tires' pressure.
• Inflate tires to the recommended PSI as listed on the driver’s door jamb.
• Inspect tires for uneven wear and replace if necessary.