Here's a breakdown of how to approach this:
1. Diagnose and Fix the Blue Smoke (Oil Burning): This is the *most crucial* step. Blue smoke is almost always a sign of one or more of these problems:
* Worn Valve Seals: These seals prevent oil from leaking into the combustion chamber. Worn seals are a common cause of blue smoke, especially on higher-mileage vehicles.
* Worn Piston Rings: Piston rings seal the combustion chamber. Worn rings allow oil to seep past into the cylinder, burning and creating blue smoke.
* Bad Valve Guides: These guides keep the valves in place and prevent oil leakage. If they are worn, oil can leak down into the combustion chamber.
* Cylinder Head Gasket Leak: A leak in this gasket can allow oil to enter the cylinders.
* Crankshaft Seal Leak: A leak in this seal can allow oil to get into other engine components, ultimately leading to burning oil.
You MUST have a mechanic diagnose the cause of the blue smoke. This requires a compression test, leak-down test, and likely an inspection of the valve train. Attempting to fix this yourself without proper knowledge could lead to further damage.
2. Once the Oil Burning is Fixed, THEN Consider MPG Improvements: After the mechanical issues are resolved, you can consider these steps to improve fuel economy, but they won't have much impact until the oil consumption is under control:
* Tune-up: New spark plugs, wires, distributor cap and rotor, and air filter are essential for optimal engine performance and fuel efficiency.
* Oxygen Sensor: A faulty oxygen sensor can significantly impact fuel economy.
* Fuel Filter: A clogged fuel filter restricts fuel flow, reducing efficiency.
* Throttle Body Cleaning: A clean throttle body ensures proper air intake.
* Proper Tire Inflation: Under-inflated tires increase rolling resistance, reducing MPG.
* Driving Habits: Avoid jackrabbit starts and aggressive acceleration. Maintain a consistent speed on the highway.
* Weight Reduction: Removing unnecessary weight from the vehicle can improve MPG (but this might not be practical).
In short: Don't waste time or money on MPG improvements until you fix the serious oil-burning problem indicated by the blue smoke. Ignoring it will likely lead to catastrophic engine failure. Get a professional mechanic to diagnose and repair the oil consumption issue first. Then, and only then, should you focus on minor fuel efficiency improvements.
