Originally Posted by Dizle
My car <---------- is getting 29-30mpg's, last tank was about 50/50 city/ highway driving like a grandma in the city and 70-75mph fwy. Wish it were better, I've replaces spark plugs, cleaned MAF, disconnected the battery for 15-20 mins, ran a can of sea foam through a tank, checked tire pressures. I just replaced the fuel filter, probably first one @ 75k but who knows hoping that will get me a few more miles. Still not bad I guess, does short shifting in this car decrease the mileage? I shift at like 13, 20, 28, 35 and 40mph (no tach :( ) or so driving like a grandma seeing what kind of mileage I can squeeze out of her minimal a/c.
Where can I get a drop in replacement filter to get rid of this lifetime thing? Autostore can't look it up it says not replaceable. I'd like to do the cabin air filter as well.
What else can I do maintenance wise or after market to improve fuel economy?
Sorry to kind of hijack your thread
Short shifting in my experiments does not improve economy. Fuel consumption is directly related to load. The lower the load - the less fuel consumed. RPM's don't really mean anything when you consider the air volume at high RPM's and light load. The engine speed can increase dramatically without much of a change in air volume. The amount of air volume entering the engine is what determines fuel delivery and the amount of load an engine is under will be the #1 varible in air volume. Shifting into a high gear too soon will increase load and result in a reduction of fuel economy.
I've always been a skeptic when it comes to additives especially tank-based injector cleaner. Adding a solvent to my tank especially with an old fuel filter is likely to loosen material trapped in the filter and do the opposite of what you want. Decarbing top ends will improve fuel economy and driveability but there is really only a few ways to do it properly and they can be dangerous to the person and to the engine if performed incorrectly. I chose not to explain this procedure in public forums like this simply due to Murphy's Law.
Other than having a top end decarb done professionally every 60,000 miles or so, running high quality petrol gasoline, keeping your air filter clean, tires properly inflated and cargo weight to a minimum - the rest is environmental, fuel blend and driving habit related.