Since I got into the whole "Fuel Economy" thing I would have to say that poor maintenance is the number 1 reason for poor economy and wasted fuel.
I have been turning wrenches for many years and worked at all kinds of garages. Every time I do an oil change I also do what most people just check off on the sheet and this includes checking all fluid level including diffs and transfer cases and make sure all grease fittings (if equipped) are lubed and the most important part of the service (besides a test drive) is checking the tire pressures.
I would say 90% of the hundreds of thousands of tires I serviced including tractor/trailer tires are under-inflated. I am not talking EcoModder pressure settings, but
manufacturer settings. Out of that 90% of tires, 50% of those are extremely under-inflated to near half or less than half of the recommended pressure. These are mainly the cars with a fresh oil change sticker from a Quick Lube or a ............er............hm........Department Store.
This percentage has actually changed since I started working at this new garage where everyone does their job correctly and we have loyal customers that return regularly. When I started working there I was impressed with the customer loyalty and return customer base. When a regular comes in, his/her tires are usually good to go 99% of the time and we usually don't find anything wrong with the vehicle unless it's a recent failure of a component. I couldn't believe the fleet of trucks that we service regularly that have anywhere from 700,000 to over a
million miles on them and still have the
original kingpins, tie rods, drag links, spring bushings, U-joints, etc and even several high mileage cars with original suspension/steering parts on them.
So it all comes down to maintenance and who is doing it for you. Seems like the owners who do their own do a better job than those who go to the Quick Lube or Walmart and buy milk and baby clothes at the same place
There are actually very few people who do their own maintenance anymore and the shoddy shops and Flat Rate dealers that exist in our world are probably doing you more harm than good by showing you a checksheet with a list of performed duties that were not done. This gives you that false sense of security that you are good to go. You cannot charge $20.00 for an oil change and make any money unless you simply change oil and filter and fill. A Flat Rate mechanic at a dealer or shop on average has to complete the job in 20 minutes or less to break even and this includes racking up the vehicle after they test drive (or do they test drive?) your car to listen and feel for safety issues.
If you go to one of these places that have this "Checksheet" they give you, I bet if you actually took the car home and went over the sheet yourself, you would find it to be a lie. You can tell if a diff plug on a pickup has been removed for a level check and you don't even have to bend over that far to see. One trick I seen before is a customer would let 10-15 pounds of air out of one tire and then have it serviced. They would be that same customer that you see in the parking lot checking his tire pressures and looking under the hood and under the car even though you just been there. That same customer would be the guy ripping your manager a new asshole at the service desk if you did not do your job correctly.
How many shops do you go to and actually see the mechanic or service writer take the car on a short spin down the road before bringing it into the service bay? How can they say the wheel bearings or suspension components are fine if they never drove it? Sometimes a "Shakedown" on the rack does not reveal what a simple 1 minute test drive can.
Just a few things related to fuel economy that I wanted to throw out there.