Faulty oxygen sensor: The oxygen sensor measures the amount of oxygen in the exhaust gas and helps the engine adjust the fuel mixture accordingly. A faulty oxygen sensor can cause the engine to run rich, which can lead to decreased gas mileage.
Dirty or clogged fuel injectors: Fuel injectors spray fuel into the engine's cylinders. Dirty or clogged fuel injectors can prevent the engine from getting the proper amount of fuel, which can lead to decreased gas mileage.
Faulty mass air flow sensor: The mass air flow sensor measures the amount of air entering the engine. A faulty mass air flow sensor can cause the engine to run rich, which can lead to decreased gas mileage.
Tire pressure: Underinflated tires can increase rolling resistance and reduce gas mileage. Make sure your tires are inflated to the proper pressure as specified in your vehicle's owner's manual.
Bad spark plugs or ignition wires: Faulty spark plugs or ignition wires can cause the engine to misfire, which can lead to decreased gas mileage.
Faulty fuel pump: A failing fuel pump can cause the engine to run lean, which can lead to decreased gas mileage.
Incorrect driving habits: Aggressive driving, such as rapid acceleration and braking, can reduce gas mileage. Try to drive smoothly and avoid unnecessary acceleration and braking.
Additionally, if your Tahoe has 4WD, make sure you're not driving in 4WD mode when you don't need it, as this can reduce gas mileage.
