(I'm new to this Forum) I just purchased a used 2008 INFINITY EX35, in EXCELLENT condition, with only 63,908 miles and complete service history with ALL service records. Yeah, I couldn't believe it at first either. OK, so I am old and the last Nissan I purchased was when it was still Datsun. It was a 260Z. I never thought I would purchase another Nissan vehicle but here I am. Anyway, I wanted to check my mileage since I have heard a lot about the awful miles per gallon for this vehicle. My wife and I drove the EX35 a total of 230.9 miles yesterday and upon return I filled the tank with ONLY 9.076 gallons! That equates to 25.44 miles per gallon!!! On three occasions, I even had to "floor it" to pass a slower vehicle. Does that sound appropriate? Of course, I did use Cenex fuel, which has no Ethanol. Don't know if that made a difference or not. Sure would love to hear from anyone regarding these miles per gallon numbers. I checked and re-checked my figures. Has anyone else had these miles per gallon and is this normal?

Welcome. Although I do not own an EX35, I do own a vehicle I believe shares the same engine and platform (350Z with a manual trans). Believe it or not, 25.44 mpg is considered in its normal range for highway driving. It's not a fuel sipping Versa, though it is a bit thirstier than it's competition, especially with the rise of hybrids. But the EX is considered a luxury vehicle and is thus a bit heavier with stuff like AWD, a fancier interior, additional seats, more gadgets / gizmos, and it's as aerodynamic as a brick because it's a Crossover, and most of those things carry an inevitable gas mileage penalty. My Z gets maybe 27-28mpg on the highway but so much depends on other factors, including my driving style, the hills, traffic, if I keep the speed reasonable, if I run the a/c, or the windows open, the air pressure in my tires, the age of my filters, how long I let it warm up, how much weight I'm carrying, etc. I have coaxed 30 mpg a couple times, but the conditions had to be right to do it, and it sapped some of the fun out of driving it. And I smile a lot more when I accelerate harder than if I hypermile.

My point is there are many things that influence gas mileage, and you are right, ethanol can influence mileage. Ethanol is not as efficient as ethanol-free, so the difference made by the fuel depends on the % of ethanol used in it. So Ethanol free should give you slightly better gas mileage than "E10", (E10 is up to 10% ethanol and the most common blend), but the reality is the difference is small enough that running underinflated tires , for example, would more than negate any savings derived by the amount of ethanol in your last fillup. As far as "flooring it" to pass, that may or may not be normal depending on the circumstances and conditions, especially if it's an automatic. It's difficult to say from here whether or not there's something not running properly. My unprofessional guess is its running ok.

Since it sounds like your car is operating within the normal range for gas mileage. before paying to see a mechanic, I'd recommend trying some hypermiling techniques, which include things like coasting, keeping your speeds down, reducing unnecessary weight in the car,keeping a close watch on your air pressures, and filters, not warming up your car, etc etc, and see what happens. One idea might be for you to try the hypermiling stuff and your wife drive as before and see if there's a significant difference. Might be a fun experiment and you might get a little closer to 30mpg, But then again, there is the fun factor to consider. At the end of the day, you have a fun vehicle to drive, so enjoy the driving. Hope that helps.

Thank you for your excellent insight. I take special care of all my vehicles (oil changes at 3,000 miles, new filters, proper fluid levels, using the best fuel available, etc). Good to know my mileage is rather normal for my driving. Not sure what people who complain about gas mileage are thinking. In my opinion, getting 25+ mpg in a vehicle like this is pretty darn good. And YES, you’re right, it’s a lot of fun to drive. Thanks again.