why does my GMC Sierra T1XX (2019-Present) have poor fuel economy?

Discover how to diagnose and fix poor fuel economy issues in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, tire pressure gauge, socket set, torque wrench, fuel pressure gauge, multimeter.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery before working on electrical components.

2. Address Engine Fault Codes

• Use the OBD-II scanner to retrieve and document any error codes.
• Clear the codes and take the vehicle for a test drive to see if they reappear.
• If codes related to the fuel system or engine performance are present, proceed with specific repairs as indicated by the codes.

3. Tire Maintenance

• Check and adjust tire pressure to the manufacturer's recommended levels (found in the owner’s manual or on a sticker inside the driver’s door).
• Inspect the tread for uneven wear; replace tires if necessary.

4. Air Filter Replacement

• Locate the air filter housing and remove the cover.
• Take out the old air filter and inspect it; replace with a new one if it's dirty or clogged.
• Reassemble the air filter housing securely.

5. Fuel System Inspection

• Inspect fuel injectors for clogs or leaks; clean or replace as needed.
• Check the fuel pressure using a fuel pressure gauge; ensure it meets manufacturer specifications.
• Repair or replace any damaged fuel lines.

6. Oil Change (if necessary)

• Check the engine oil level using the dipstick; change oil if it appears dirty or is below the minimum mark.
• Use the recommended engine oil type as specified in the owner’s manual.
• Replace the oil filter during the oil change.

7. Exhaust System Check

• Inspect the exhaust system for leaks or damage (especially around the manifold and catalytic converter).
• Repair or replace any faulty components to restore engine efficiency.