I. Maintenance is Key:
* Regular Tune-Up: This is the single most impactful thing you can do. Include:
* New Spark Plugs: Worn plugs misfire, wasting fuel.
* New Air Filter: A clogged filter restricts airflow, reducing engine efficiency.
* New Fuel Filter: A dirty filter restricts fuel flow, impacting performance and economy.
* Clean Throttle Body: A clean throttle body ensures proper air intake.
* Check PCV Valve: A faulty PCV valve can cause excessive oil consumption and reduce fuel efficiency.
* Tire Inflation: Properly inflated tires significantly impact gas mileage. Check your tire pressure regularly (including the spare!) and inflate to the pressure recommended on the sticker inside your driver's side doorjamb. Underinflation is a major fuel waster.
* Wheel Alignment & Balance: Poor alignment and unbalanced wheels increase tire wear and reduce fuel efficiency.
* Transmission Fluid Change: Ensure your transmission fluid is clean and at the correct level. A slipping transmission wastes fuel.
* Oxygen Sensor(s): Faulty oxygen sensors can significantly impact fuel economy. A diagnostic check can identify this.
* Mass Airflow Sensor (MAF) Cleaning: A dirty MAF sensor can lead to inaccurate fuel mixture calculations. Cleaning it might improve fuel economy. (Only clean it – don't replace it unless necessary)
II. Driving Habits:
* Smooth Acceleration and Braking: Avoid jackrabbit starts and hard braking. Accelerate gradually and anticipate stops to reduce braking.
* Maintain Consistent Speed: Cruising at a steady speed is more fuel-efficient than constantly accelerating and decelerating.
* Avoid Idling: Turn off your engine if you'll be stopped for more than a minute.
* Use Cruise Control (on highways): Cruise control helps maintain a consistent speed, improving fuel economy.
* Reduce Weight: The heavier your vehicle, the more fuel it consumes. Remove unnecessary weight from your Trailblazer.
* Plan Your Routes: Avoid rush hour traffic whenever possible, as stop-and-go driving significantly reduces fuel economy.
III. Minor Modifications (Consider Carefully – Cost vs. Benefit):
* Aerodynamic Improvements: While significant improvements require major modifications, simple things like removing roof racks when not needed can help slightly.
* High-Mileage Oil: Using a high-mileage oil formulated for older engines can help maintain engine performance and potentially improve fuel economy. Consult your owner's manual.
IV. Professional Diagnosis:
If you've addressed the maintenance and driving habits and still see no improvement, take your Trailblazer to a trusted mechanic for a diagnostic check. They can identify any underlying mechanical issues impacting fuel efficiency.
Important Note: The 2004 Chevy Trailblazer is not known for stellar gas mileage. While you can improve it with these steps, don't expect a dramatic increase. Realistic expectations are key. Expect incremental improvements rather than a sudden leap in MPG.
