why does my Cadillac Escalade T1XX (2021-Present) get poor gas mileage all of a sudden

Symptoms

• Check engine light illuminated
• Rough idle during engine operation
• Noticeable loss of power during acceleration
• Decreased mileage (fewer miles per gallon)
• Unusual fuel odors around the vehicle
• Increased emissions from the exhaust

Diagnostic Steps

1. Scan the vehicle for error codes using an OBD-II scanner to identify potential fault codes.
2. Check the fuel system for leaks, including inspecting fuel lines and connections.
3. Inspect the air intake system for blockages or leaks, focusing on the air filter and intake ducts.
4. Test fuel pressure to ensure the fuel pump is functioning correctly.
5. Inspect the exhaust system for any restrictions or blockages, including the catalytic converter.
6. Evaluate the engine performance, checking for issues such as misfires or rough running conditions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Replace the Air Filter

• Remove the air filter housing cover using a socket set.
• Take out the old air filter and inspect it for dirt and clogs.
• Replace with a new air filter (OEM recommended) if dirty.
• Reinstall the air filter housing cover and secure it.

3. Check and Replace Fuel Filter

• Locate the fuel filter (may be within the fuel pump module).
• Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect the fuel lines using a fuel line disconnect tool and remove the old filter.
• Install the new fuel filter, ensuring correct orientation.
• Reconnect fuel lines and replace the fuel pump fuse.

4. Inspect Spark Plugs

• Remove the ignition coil cover using a socket set.
• Remove the ignition coils and inspect spark plugs for wear or fouling.
• Replace spark plugs if they show signs of wear or irregularities.
• Reinstall ignition coils and cover.

5. Check and Clean the Mass Air Flow Sensor (MAF)

• Locate the MAF sensor in the intake tract.
• Disconnect the electrical connector and remove the sensor.
• Use MAF cleaner to clean the sensor element carefully.
• Reinstall the MAF sensor and connect the electrical connector.