I drive a 1995 Toyota Avalon on my daily commute to and from school. On trips through New Jersey that I have taken on vacation, my Avalon has exceeded 31 mpg with the Sunoco gasoline (getting 31.6 mpg on one return trip, 30.06 mpg on another trip) that they sell on the New Jersey Turnpike, so I decided to try switching from BJs gasoline to Sunoco gasoline, hoping that the gasoline that Sunoco sells in New York is the same as the gasoline they sell in New Jersey.

I have been averaging 25.63 mpg on the BJs gasoline, never touching 28 mpg. With my first tank of Sunoco gasoline, which was a mixture of BJs gasoline and Sunoco gasoline because it was my first fill-up, I got 28.30 mpg, and if it is any indication, I should be exceeding 28 mpg regularly in the future. This might seem unremarkable, but before I started driving the car almost two years ago, it never exceeded 22 mpg and its average fuel economy was 20 mpg, which means that I have increased its efficiency by 40% within the last two years.

The main improvements in fuel economy were made by putting Chevron Techron fuel injector cleaner in the gas tank semi-regularly, by changing the air filter regularly and by using the Sunoco gasoline. Minor improvements were made by changing the spark plugs, by using a K&N air filter and by running an Auto-RX treatment, although the fuel economy declined while the treatment was in the engine. It is worth noting that the air filter had not been changed in the life of the vehicle and Chevron Techron Fuel Injector cleaner had never been put in the tank. Other things that were done, which should be unrelated to fuel economy, were changing the PCV Valve on a regular basis (it was never changed in the life of the vehicle), changing the timing belts, resealing the engine (it was leaking oil), changing the fuel filter (which was also never done in the life of the vehicle) and using a Purolator Oil Filter.

I figured that it would be a good idea to share this information, with the hope that someone else finds it useful.

 

When I used to live in the DC area and drive a Yamaha 550 motorcycle, I too had discovered the benefits of Sunoco. The smaller the ICE, the more important that all of the basics, including fuel quality, are optimal.

Bob Wilson

 

I keep a notebook of my fuel economy, fuel purchased, and where I got it. I have noticed significant differences not only in different gas station brands, but even among individual stations.

 

Okay... here's the kicker.... there's ALWAYS air space in the tank when you fill up. In the Ford Escape, there is 3 gallons of air space in fact, when on level ground.

The differences you are seeing from station to station are probably due to the ground at the station not being 100% flat. If you just by luck, happen to park with the gas cap on the "high end" of the car, more air will escape, and more gas will go in, making it appear you got fewer MPG ( since it took more gallons to fill-up ). The converse is also true. Parking with the gas cap on the low side will allow fewer gallons to go in, making you think you got higher MPG.

Now you may think, no big deal... how much could this really add up to?
A Lot is the answer. 10% is typical, with the slightest slope.
On a big slope, with gas cap on the high end, I can put 18 gallons in my tank. If the cap is on the low end, I can only put in about 12 gallons.
This is a HUGE... like 33% difference.
-John

 

That could explain why I got 28.3 mpg on my first fill-up and have averaged around 26.6 mpg on my fill-ups since then (not including the 28.3 mpg figure in the average). It is still a 1.1 mpg improvement over the BJs gasoline, but it is not the improvement that I thought it was.

Edit: Averaging the 5 fill-ups I did at BJs prior to using the Sunoco gasoline, my fuel economy with BJs gasoline was 25.6 mpg, so I saw a 1.0 mpg improvement with the Sunoco gasoline, which is even worse than the 1.1 mpg improvement that I thought it was. On the bright side, I put Chevron Techron Fuel Injector cleaner into the tank two tanks ago (I am starting to see an improvement) and I am considering getting low rolling resistance Michelin Energy MXV4 Plus tires when I get new tires later this year, which I expect to improve my fuel economy by approximately 5%.

 

GPSMAN1 is on target about station differences, etc. I fillup at the same station and the same pump (I do have 1 other pump I use if the one I like is occuppied) every time. This eliminates several variables at once. I also believe in Sunoco. Here in Dallas there are no Sunoco stations but there are QTs (like 7-11) which I believe use Sunoco from their Tulsa refinery.

On another note about tires. If your are running at owner's manual tire pressures try adding air to the sidewall maximum. This should give you a little stiffer ride and 3-5% more in mpg.

 

I forgot to mention that the 1.0 mpg fuel economy increase is with some air conditioner usage starting around the time I started using Sunoco gasoline with no air conditioner usage prior to that point.

abowles, they do that at gassavers.org and one person had uneven wear such that the entire center of his tires were worn completely and the materials under the rubber were visible. With that in mind, I am a bit hesitant to overinflate the tires, although I do inflate them to 2 psi above the manufacturer's specification.