1. Proper Maintenance is Crucial:
* Tune-up: This is the single most impactful thing you can do. Ensure your spark plugs, wires, distributor cap and rotor (if applicable), air filter, and fuel filter are all new and functioning correctly. A dirty air filter restricts airflow, leading to inefficient combustion. A clogged fuel filter restricts fuel flow. Worn spark plugs and ignition components cause misfires, wasting fuel.
* Oxygen Sensor: A faulty oxygen sensor prevents the engine from accurately adjusting the air-fuel mixture, leading to poor fuel economy.
* PCV Valve: This valve helps vent crankcase gases. A faulty one can lead to increased fuel consumption and emissions.
* Tire Pressure: Keep your tires inflated to the pressure specified on the sticker inside your driver's side doorjamb (or in your owner's manual). Under-inflated tires increase rolling resistance.
* Wheel Alignment & Balance: Improper alignment and unbalanced wheels increase friction, reducing fuel efficiency.
* Transmission Service: For an automatic transmission, regular fluid and filter changes are essential for smooth shifting and efficient operation.
* Check for Leaks: Inspect for any fuel leaks. Even a small leak wastes fuel.
2. Driving Habits:
* Gentle Acceleration: Avoid jackrabbit starts. Accelerate smoothly and gradually.
* Maintain Speed: Cruising at a constant speed, especially on the highway, is more fuel-efficient than constantly accelerating and braking.
* Anticipate Traffic: Smooth driving avoids unnecessary braking and acceleration.
* Avoid Idling: Turn off your engine if you'll be stopped for more than a minute or so.
* Use Cruise Control: On the highway, cruise control helps maintain a consistent speed and can improve fuel economy.
* Lighten the Load: Reduce the weight in your car. Extra weight means more fuel consumption.
3. (Less Impactful, but worth considering):
* Fuel Additive: Some fuel additives claim to improve gas mileage. Their effectiveness varies, but they might offer a slight improvement. Read reviews carefully.
* Aerodynamics: While you can't change the Eldorado's body style, removing unnecessary roof racks or other external accessories can slightly improve aerodynamics.
Realistic Expectations: Don't expect a dramatic increase in MPG. A 10-15% improvement through maintenance and driving habits is possible, but a larger gain is unlikely. The Eldorado was not designed for fuel efficiency. The biggest gains will come from addressing mechanical issues.
Before undertaking any significant repairs yourself, consider the cost of parts and labor versus the potential fuel savings. It might be more cost-effective to focus on the simple, inexpensive maintenance items first.
