1. Maintenance is Key:
* Tune-up: This is paramount. Ensure your air filter is clean (replace if dirty), spark plugs are new and gapped correctly, and the ignition wires are in good condition. A dirty air filter restricts airflow, forcing the engine to work harder. Worn spark plugs and wires cause misfires, leading to wasted fuel.
* Fuel System Cleaning: A fuel injector cleaning (either through a professional service or using a fuel injector cleaner additive) can improve combustion efficiency. A clogged fuel filter also restricts fuel flow. Replace it if needed.
* Check for Leaks: Inspect for vacuum leaks in hoses and the intake manifold. Leaks disrupt the air-fuel mixture.
* Tire Pressure: Properly inflated tires reduce rolling resistance. Check your tire pressure regularly (at least monthly) and inflate to the pressure recommended on the sticker inside your driver's side doorjamb.
* Oxygen Sensor: A faulty oxygen sensor prevents the engine from getting the correct air/fuel mixture. Have this checked if your fuel economy has suddenly dropped significantly.
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor can also lead to poor fuel economy. Consider cleaning it (carefully, with MAF sensor cleaner) or replacing it if necessary.
* Transmission Fluid: If the automatic transmission fluid is old or dirty, it can negatively impact fuel economy. Consider a fluid change (and filter if applicable).
2. Driving Habits:
* Smooth Acceleration and Braking: Avoid jackrabbit starts and hard braking. Gentle acceleration and smooth braking conserve fuel.
* Maintain Steady Speed: Cruising at a consistent speed is more fuel-efficient than constantly accelerating and decelerating. Use cruise control on highways to maintain a constant speed.
* Anticipate Traffic: Look ahead and adjust your speed accordingly to avoid unnecessary braking and acceleration.
* Avoid Idling: Turn off your engine if you'll be stopped for more than a minute or so.
* Reduce Cargo: Excess weight decreases fuel economy. Remove unnecessary items from your car.
* Aerodynamics: While you can't change the car's shape, avoid carrying things on the roof rack that increase wind resistance.
3. Mechanical Upgrades (More Involved & Costly):
* High-Flow Exhaust: A well-designed performance exhaust can slightly improve fuel economy in some cases (though this is not always the case and depends on the design). However, this is primarily designed for performance, and the benefit to fuel economy might be marginal.
* Underdrive Pulley: Reduces parasitic losses from the alternator, but this can stress other engine components and potentially reduce lifespan if not done properly. Not recommended unless you're already making significant other performance upgrades and knowledgeable about engine mechanics.
Important Considerations:
* The 3800 Series V6: Your GTP's engine is naturally thirsty. Significant improvements are possible, but don't expect miracles.
* Professional Diagnosis: If you're unsure about any of these steps, take your car to a qualified mechanic for a diagnosis. They can pinpoint specific problems impacting your fuel economy.
By consistently applying these tips, you can reasonably expect to improve your Grand Prix GTP's fuel economy. Remember that a combination of diligent maintenance and mindful driving will yield the best results.
