I am the original owner of a bone stock 2001 Maxima. I first noticed I was getting poor gas mileage around fall of 2003. I took it to the dealer and they found nothing wrong. I took it back again in January and they reset the computer and told me that it should cure my problem. They also warned me that using regular 87 octane gas would cause this, but I'm skeptical. But I have been running 91 octane since then and still no improvement. I'm getting around 12-13 miles per gallon, when I used to get around 18-19 when I first bought the car. The car only has 16,xxx miles on it, and is driven very gently, mostly city driving.

Has anyone had similar problems or know what I should check first? The dealer has already checked the spark plugs, the computer for codes, the air filter, and found nothing. Thanks!

 

Beats me. I have always had poor gas milege. I average about 17 city/22 highway, but I think it's due to my driving style more than anything .

 

I used to get about 13 - 15 mpg (80 % city driving; 27-28 mpg highway). I had dealer do fuel induction service which included throttle body cleaning (app. $100) and this helped. I'm feeling better performance and mileage improved to about 15 - 17 mpg (27 - 30 mpg on the highway). Just my experience ...

 

you should run fuel injector cleaner on a regular interval if you haven't then you might try that. Pluse winter gas gets much worse gas mileage than summer gas(different additives).

 

Try BG-44K

 

Also, take a long trip like 200 miles... see if you notice any difference in mileage. Also, consider switching gasoline brand.

 

I am getting same bad mileage (10-12) on my stock 2000 GXE with 46000mi. My friend has a 2003 GLE, he gets 17.4, so i dont think its the gas. I've been to a mechanic, he said that my spark plugs need changing. Otherwise he didnt see anything wrong with the car. It idles a little rough, and I feel like it lacks power, but thats subjective, so I dunno if its just my imagination. It doesnt have any problem revving to redline either.

Tim

 

try sea foam, fuel injection, don't use the heater, try not to brake as hard, and keep the rpm's low..the combination of those should increase ur mpg

 

I noticed a drop this winter. Lots of people have said it is due to additives in the gasoline. I am planning a full system flush in the spring with an injection cleaning! good luck.

 

clean your fuel injectors... get a transmission flush..
that helped me

 

Check you PVC valve

 

Thanks for the help. I've already tried switching gasoline brands but that didn't do anything at all. A car this new should not have this problem. I wonder if we just got a lemon. The spoiler cracked for no reason and the gas cap cover also had some cracking issues...

 

poor gas mileage is a sign of something not working right in the engine IMO. Hopefully its not a lemon and you can get things worked out with a fuel injection cleaner, new spark plugs, and tranny flush

 

Are you serious?

 

Sea foam??? Should I change my blinker fluid too?

 

http://www.seafoamsales.com/

 

Definitely something not right.....I have an '01 (albeit stick) and the last two fill-ups have yielded 22.1 and 22.5 mpg on a mix of city, highway and variable-speed two-lane back-road driving -with winter gas, mind u.

 

I don't have the answer. : When I read your post , you were describing my car, my problem.. exactly what my car is doing. My 2001 Nissan Maxima gle. With 176,xxx on it runs Strong. Very dependable... Changed all 4 O2 sensors, coolant temperature sensor. Please can someone please tell me why my car is only getting 12 13 miles to the gallon. ??? 6)5/19

 

maf, you dirty little necro

 

also a slipping tranny, low tires and bade wheel bearings can tank mpg like in my case. also bad sensor data or bad sensors. in my case i get no CEL