Dramatically increased MPG overnight

[matron820]

So, I have a 2011 Nissan Rogue, SV. I have about 10,500 miles on it. I live in south florida, always fill up with the low grade gasoline, and drive about 70% city 30% highway. I try to drive with a pretty light foot most of the time. For the past 10 months or so, I have consistantly gotten about 20.8 mpg- 21.5 mpg. I drove my car yesterday and as I was driving the mpg was going up, extremely fast, it went from 21mpg to 25.5 mpg in about 45 min of driving. Ive done nothing different except getting an oil change about a week ago, also went to a diff gas station a day ago but got the same 89 low grade fuel I always get. Im not complaing, im just wondering whats happened, its stayed at about 25 mpg, and with the amount of miles I have left in the tank and the amount of miles ive driven it seems pretty accurate so far. Is this really the improved mpg from breaking in the engine? If so does it really happen overnight like that??

[casperfun]

Well if you entered the highway during the 1st minute and exited the highway on the 45th minute, then I wouldn't be surprised. My mpg on the trip computer goes up exponentially when traveling on a highway. In a rathe quick fashion I must say.

[matron820]

Well if you entered the highway during the 1st minute and exited the highway on the 45th minute, then I wouldn't be surprised. My mpg on the trip computer goes up exponentially when traveling on a highway. In a rathe quick fashion I must say.

Haha, nope I was in the city when it happened, so weird, im just hoping it stays this way.

[kerrton]

This is interesting, I'd suggest sticking with the new gas station and seeing if your mpg's stay constant.

In addition to octane there are other differences between gasoline "brands" or manufacturers. In Alberta for example, there are basically 2, maybe 3 refineries that produce gasoline for everyone (Shell, Esso, PetroCan, Safeway...). Once the gasoline is delivered from the refinery, some retailers choose to put additives into the fuel such as Shell and PetroCan. These additives allow your engine to run cleaner, avoid nasty buildups in the fuel system and combustion chamber, valves etc.. Retailers such as Safeway do not add any of these additives to their fuel, they sell it as is from the refinery. So over time in theory your car should run better on Shell gasoline than Safeway - how significant the benefit is in reality, if any, is up for debate I'm sure. Also, would you notice an instaneous benefit in terms of efficiency/mpg? Probably not.

The logical next step would be to continue purchasing your gas from the same retailer and note the mpg's over time, as well as driving style etc..

[walt227]

I am experiencing somewhat of a similar improvement but with a more identified causation. I too own a 2011 SV AWD with less that 10,000 miles. After reading a previous thread in this forum related to differences in ethanol vs non-ethanol gasolines on the "cvt lag or vibration" many Rogue owners experience, I decided to give ethanol free gasoline a try to see if it would diminish or lessen the "lag/vibration" that occurs in cvt transmissions between 20 to 40 mph. Using ethanol free did not improve the cvt performance but has resulted in 3 to 4 mpg gallons improvement in a city/highway blend of driving (23 mpg vs 26/27 mpg). I have yet to be able to see what the ethanol free will do on a primarily highway trip. As others have mentioned, the mpg display readout has always been inaccurate (for me and I think others) to the tune of between 1 to 2 mpg. So, I have been basing my mpg estimates on manual calculations. In any event, I seem to be getting improved gas milage based on switching to ethanol free gasoline rather than some unaccounted for anomaly. My "new" milage appears closer to the mpg estimates given on the sticker as opposed to my "old" milage which seemed, for the most part to be below that advertised on the sticker which I believe is 21/26 for an AWD. I don't remember the source, but I have a recollection or having read or being told that EPA milage estimates are based on the use of ethanol free gasoline. While I have not found a definitive article or source for that belief my "experiment" suggests this might be true. If anyone knows this to be a fact or not, I would appreciate knowing the answer. In any event, I would like to continue using ethanol free but it is sometime difficult to find ethanol free stations I have found several that are in the routes I normally travel--at least closer to home. Now, depending on the price of gas, the ethanol free has cost me between 10 and 15 cents more per gallon. So, at an improved mpg of 3 to 4 mpg per tankful (roughly 16 gals x's 3= 48 more mpg per tankful) I am at least breaking even or a bit ahead on the cost per gallon vs increased milage using ethanol free. If we ever see ethanol subsidies disappear than I think this will be a moot point. Now, I do not know or cannot say that my Rogue likes the ethanol free better than the ethanol gasoline but I have read some some literature citing the benefits of either.

Sorry for the long post or rambling and also for the fact that it may be a bit off topic. More often than not I do not have a lot to contribute so I try to jump in when I can.

[casperfun]

I have a better chance of finding bigfoot than an ethanol free gas station. Personally, I think ethanol is a scam and never really saves us money at the pump. On top of that, it's tendancy to ruin engines supposedly and taking away from a food source.

I believe hybrid or electric engines is more practical than the use of ethanol IMHO.

[bill875]

Find a gas station with Ethanol-Free Gasoline... http://pure-gas.org/

[MichaelD1953]

I could not agree with casperfun more. Ethanol is a rip any way you look at it. It does screw up engine seals and such. Even the guy that repairs our lawn equipment and tractors said he has seen more than one engine have problems or die because of the crap and look at the damage it is doing to the food supply.

[MichaelD1953]

Whoah, I just noticed, got to find the profile page to change my car. That is a 2011 Rogue SV with full SL package. Hot Cayenne Red.