Bought as certified used from Youngblood Nissan 1 year ago. Was getting 28mpg in town, 30 mixed, 32/33 highway cruise at 80. About 2 months ago sudden drop in mpg now 20 in town, can squeeze 23 out on highway.

Took to my mechanic said nothing wrong with fuel system but transmission felt odd, qualified not certified to work on CVT. Took to original dealer, they cant find anything wrong. Invited me back to test drive it with a mechanic to demonstrate the minor transmission shift changes I have noticed.

Pretty ridiculous to pay 13k for a certified used and get great mpg for a year (which is why i bought it to begin with), then lose 1/3 of my economy with no driving habits changes, and the master tech at the dealer cant find the problem so they want to put it on me to demonstrate what is wrong. They agree its a problem, but argue well if it was that bad it would smoke, etc. Bunch of crap. It's getting horrible mileage.

I've owned the car a year I bought a $3000 warranty to go with it. Keep the car 2 weeks if you have to and fix it but no, I need to be the one to demonstrate a problem. I find PLENTY of complaints about fuel economy on this model on the internet. Seems to be a well known problem and nobody knows why. Nissan? Why don't you explain... you built it.

I bought the car brand new last spring, and was getting GREAT gas mileage - even on a drive from Seattle to Las Vegas I averaged 30-40mpg. Then, in January this year, I noticed my mpg started tanking. I was usually filling at Costco, and when I talked to the dealership, they assured me it was the gas, and to switch to a few tanks of Chevron premium to see if the issue resolved. Of course it didn't, and when I called the dealership back, they said it was b/c the gas stations were switching to their spring mix, so it must be that I've been getting old gas. THEN they told me that there isn't a problem w/ the fuel system b/c even a minor issue would make my check engine light come on. I even called a different dealership, and was told basically the same thing.

I contacted Nissan directly, and was told to take it in to have an air flow test done, so we'll see how that goes!

Update from May 15, 2013: We were at a different dealership last night, and the salesman said he had received a complaint about the mpg from another customer w/ a sentra....

Bought a new 2012 Nissan Sentra SR in August 2012. Since then I've noticed that the gas mileage doesn't seem to living up to standard. According to Nissan this car should average 24 to 34 miles per gallon. I do quite a combination highway driving and city driving so I expect that my average mileage should be somewhere in the middle. Unfortunately it doesn't seem to be doing that. I filled up my take the other day, drove about 65 miles and the gas gauge indicated that I had used a quarter of a tank of gas. I'm wondering if it is a fuel pump problem or a problem with the sensor in the gas tank. Any one else out there having that same problem?