Strange increase in mpg w 2011 Sonata

Been driving my 2011 Sonata w 4900 miles on it for a year. Been using Shell regular gas & getting 26.5 mpg avg. 2 wks ago I filled up w the mid value gas by mistake. Now I'm getting 29.5 mpg! with the exact same driving habits.

An increase of mpg like that makes the mid value gas cheaper to use! Anybody else have this same experience?

TIA Scotty

Reply to
Ichnee
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How are you calculating the mpg? It would take several takes to get an average.

Reply to
Paul in Houston TX

Last time I went to my independent mechanic ( been going to him for years with no issues) he advised against using a certain brand diesel. Says he wouldnt put the other big brand in his 4WD. Maybe he,s got shares in one??????

Reply to
John

Yes, that is one possibility as it takes generally at least 5 consecutive tanks to get a good average. Another is the change from winter to summer gas formulation. A third is that maybe the mid value gas is some of the rare gas that hasn't yet been poisoned with ethanol.

Matt

Reply to
Voyager

"Ichnee" ha scritto nel messaggio news:Xns9EE0D0D9C7890tokern@198.186.190.70...

With all the hyundais I drove, the mileage was better after 10.000 Km (about 6000 miles), so, probably the reason for increase is just this, and not the fuel.

Another slight improvement in mileage I noticed was changing oil and using on my Sonata a good quality 5W20 instead of 5W40 I had before; but some people say that 5w40 oil gives a better protection to engine in hard driving conditions.

Reply to
Zotto

Some of the change could be the seasonal formulation. I get at least 2 mpg better in summer than winter. It improved about a month ago and will decline again about November. It is possible the mid grade has less ethanol to start with, thus the better mileage. The efficiency also improves after a few thousand miles on the car.

Reply to
Ed Pawlowski

I havent had this exact experience, but, I started going to this gas station that has some additive in the gasoline, and I consistently get another 3 mpg (versus all other brands) for the same type of driving each and every week. I think its a Union 76 gas station.

Reply to
ilbebauck

Ichnee wrote in news:Xns9EE0D0D9C7890tokern@198.186.190.70:

Thanks to all for the great advice.

The 26.5 mpg avg is based on 12 full tank fillups. It also agrees exactly with the 'overall' mpg averge on the odometer. The 29.5 mpg comes from the 'current' milage on the odometer.

Seasonal gas formulation and 'engine break in' sounds like the real answer. Won't know for sure till my next fillup.

Ichnee

Reply to
Ichnee

I think it has less to do with the gas, and more to do with outside air temperature.

If you know much about the tuner culture, one of their favorite modifications for increasing power is to install a cold-air intake. This pulls air from way down near the pavement, where it is cooler, rather than from an inch or two under the hood.

I've noticed the same thing in my Sonata -- better mpg in the summer than the winter. I think the colder air of winter allows the engine to produce more power at the expense of mpg, while warmer summer air can't produce as much power without knocking.

Reply to
Larry Harvilla

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