bigakphilly

2007 Maxima... I am literally getting 13.5 miles to the gallon. Months ago I was close to 18 mpg. The alternator went bad in December. Ever since then it's been at 14-13 MPG

There are no check engine light. No codes.

Anyone with any clues?

Copracr

I get 23mpg in the summer months, 17-18 in the winter. I don't know whats wrong with yours, but I'd say it was broke before you thought it was broke.

syclonemax

06 maxima with 43K miles gets same milage now as did when new, 17 18 city
21 highway. 90% of driving is city 35 mph. One time on a trip from kentucky
to south florida it got up to 22 mpg. All trip of 500 to 600 miles it stays on 19 mpg.

Scramblinman

With 164,000 miles our Max is still averaging 19-20 combined city/highway and 26-28 highway. Same as it always has

mentalmp

Well with no codes, your mileage probably depends on how hard you push the engine and the rpms at which your gears shift. For instance, what is your rpm when you're cruising on the highway at 80-100 km? (sorry, I'm Canadian ).
I suppose if you wanted as good fuel mileage as possible, you might as well remove the spare tire from the trunk!

Biscut

Mine is 07 at 98k miles. Using 93 octane I get 50/50 city/highway of 21 and on long highway trips 24 at 80mph. I wonder if the CVT has anything to do with the better mileage? Winter those numbers drop by about 1.5mpg.

Selfie13

I have an 04 Maxima, that for the past 3 to 4 years, my gas mileage was exactly like yours when it once was avg 22 - 23mpg. I gave up trying to find the problem, even the nissan dealership or any other mechanic I informed of this problem, no one ever figured it out. And I'm a very slow driver in the city and sometimes highway too, was pulled over one time for going to slow in town. ;-) Anyways, just a couple weeks ago I had to replace my valve cover gaskets to fix an oil leak. That's when I noticed my Vacuum Hose had pretty much dry rotted. Spent $5 for the small piece of tubing to replace it while I had intake manifold off, and when I had finished the repair, drove about 20 miles to the house, I noticed my gas mileage shot back up to avg. 22 mpg and has stayed that way since. So, if you get the chance, try and replace the Vacuum Hose and see if that solves your problem.

kcjames215

Depending upon how many miles you have on the car, you can use Lucas Fuel Injector Cleaner, change your spark plugs, replace air filter.

I have an 08 with 165k. I get 21 city, 23.5 mix highway/city and 29 all highway when taking long trips.