* Clogged fuel filter: A clogged fuel filter can restrict fuel flow to the engine, causing it to run inefficiently and waste fuel.
* Faulty fuel pressure regulator: A faulty fuel pressure regulator can cause the fuel pressure to be too high or too low, leading to poor fuel economy.
* Oxygen sensor issues: A faulty oxygen sensor can provide incorrect feedback to the engine control unit (ECU), which can result in incorrect fuel-air mixture and poor gas mileage.
Engine Issues:
* Worn spark plugs: Worn spark plugs can cause incomplete combustion, wasting fuel and reducing fuel efficiency.
* Vacuum leaks: Vacuum leaks can cause the engine to run lean, which can lead to poor gas mileage and performance.
* EGR valve issues: A stuck or faulty EGR valve can cause the engine to run inefficiently and waste fuel.
* Faulty thermostat: A faulty thermostat can prevent the engine from reaching its optimal operating temperature, which can negatively affect fuel economy.
Transmission Issues:
* Worn transmission: A worn transmission can cause slippage and increased resistance, which can lead to reduced fuel efficiency.
* Incorrect transmission fluid: Using the wrong type of transmission fluid can affect transmission efficiency and fuel economy.
Tire and Wheel Issues:
* Under-inflated tires: Under-inflated tires can increase rolling resistance and reduce fuel efficiency.
* Incorrect tire size: Using tires that are too large or too small for the vehicle can affect fuel economy.
* Misaligned wheels: Misaligned wheels can cause uneven tire wear and increased rolling resistance, leading to reduced gas mileage.
Driving Habits:
* Aggressive driving: Rapid acceleration, frequent braking, and high speeds can all negatively affect fuel economy.
* Idling: Excessive idling can waste fuel, especially in older vehicles.
* Heavy loads: Carrying heavy loads can increase fuel consumption.
