Ok I had ,y car for a little over six months and 9k miles on it. For the past week I noticed that my mileage is low, meaning the damm gas is burning quick. I chngd my air cleaner and added a fuel injector cleaner to see any difference and its still doing the same. I also noticed that my screen reads that its making about 16 mpg and it even droped to about 14 this morning. I called the smart asses at the stealership and first thing they said was that its normal and that i should also be using Premium. Now I'm not sure if its necessary to use premium, but if it is plz let me know. Also i dont think its normal for my car to drop to 14 mpg. I would understand if i was driving my car like crazy steping on the gas, but I've been drivng my car like a grandpa just to see how my gas comsumption is like. This is weird and its pissing me off cause i hardly drive my car. My dad has a Titan and drives it about 15-20 miles a day and can go for about 3/4 of a tank in a week. My car is doing almost the whole tank drivng half of that. Any advice?

 

I have a little over 3000 on mine and with 89 octane and mainly city driving, I am averaging about 12 mpg. I am giving it a few more thousands before I complain to the dealership.

 

I've noticed a drop in mine as well- I'm down to 15mpg from 18-19. I thought the Nismo CAI might help but, although I'm glad I have it for obvious reasons, it hasn't done **** for my MPG. I took it pretty easy on the car for the 1st 5K, then really fell in love with the engine and drive it to the max(NPI) whenever I can. BTW, I've used 93 octane since day 1.

 

have you tried reseting your fuel economy gauge? or calculate it yourself and see what you get.

 

A lot of gas stations are receiving the "winter mix" fuel from their main suppliers. There are additional additives during the winter which prevent your fuel system from freezing, etc. Also, cold air is thicker and heavier than warm air so your engine is probably running rich from lack of oxygen. My mpg went from 24 down to 20 since November, but has since gone back to about 22 with the warmer weather in the NE.

 

This subject has been discussed in previous threads. If your driving has even a moderate amount of “stop-and-go” and speeds of 45 mph or less, you won’ t get good mileage. Forget the window sticker claims. Mileage in the mid-teens is typical. That is pretty much the same for most cars.

With regard to your father’s Titan, I believe its gas tank is 40% larger than the Maxima’s gas tank (28 gallons v. 20 gallons). That may partially explain its longer range.

 

I reset it all the time esp in winter when car's benn running for a while- I reset when I take off. I'm an outside salesman so I'm driving the same route. I have to admit that I drive in manual mode much more since 5K(now have 7200 miles). I'm sure this accounts for 1-2 mpg as well, but man it's worth it- I love my car

 

Check out the below link on this issue. Also the government is mandating new MPG ratings on auto's to more accurately reflect MPG ranges. Unfortunately, the new regulation does not have to be posted on vehicles until 2008.

http://autos.msn.com/advice/article....tentid=4023628

 

thnks guys for ur help

 

$30 of gas on both vehicles wont make any difference on tank size. Thats what we usualy put on both cars/week, but good point.

 

Just got my '06 SL a few weeks ago with close to 1k miles and avg is 26.5 mpg -80% hiway. I had a '02 Altima SE that I traded it for that also got about the same. I use the premium as much as possible.

 

This has something to do with all of us getting poorer mileage. Most winter gasoline has more butane blended into the gasoline to improve your ability to start the car on very cold mornings. (The butane vaporizes better and at much lower temps than other gasoline components). But butane has less energy per gallon than most other gasoline components.

The other component that can cause reduced mileage is ethanol blended at up to 10% of the total volume. Ethanol prevents any water in your gas tank from freezing, and also replaces imported crude-oil-dependent components with a component (in the USA) made from corn. But ethanol has less energy per gallon, so the mileage will likely suffer unless your car is so out of tune that the extra oxygen in gasohol improves the combustion in your engine.

Right and Wrong. Cold air is more dense than warm air (right), so per cubic volume it contains more oxygen than warm air (not a lack of oxygen). With more dense air, you engine may be running lean, provided the computer-controlled air sensor does not measure that fact and adjust the air/fuel ratio accordingly -- which it is supposed to do.

I've noticed that my highway mileage is worse this winter than last. I will analyze the mileage I got on essentially the same trip to Chicago in Nov-Dec 2004 versus the recent mileage in Dec-Jan 2006 and provide the differences in another post on this thread when the analysis is completed.

 

I have completed the analysis comparing my Max's gasoline mileage last winter to this winter for a trip I made both winters from Colorado Springs to the Chicago area and return. The results show that the mileage this winter was less than the previous winter by about 1.5 mpg for the whole trip.

I said above that I would post the analysis on this post, but decided that it was actually a continuation of the analysis I made this winter about whether premium gasoline gives better gas mileage. So you can find the complete analysis on this thread:

http://forums.maxima.org/showthread....83#post4643683

 

have you tried replacing or cleaning your air filter? that might be a cheap solution.

 

If you read my full post on the other thread, you will see that the air filter was replaced less than a year ago. That was just over 12 K miles ago. I normally replace it between 15 K and 20 K miles.

 

Are you getting the super dirt cheap gas? I changed my oil, recharged my airfilter, and put in super unleaded (Shell i belive) & put in the techron additive seperatley this weekend and my mpg was noticably better.

 

I treat my fuel system to a Techron cleaning just before every oil change -- every 7.5 K miles. I only buy branded gasoline or from a major company like Sams or a major grocery chain. Don't think any of that is the problem.

 

I know the winter blend gas can give you lower mileage than you're used too. But that's ridiculous. Recently my girlfriend has been getting bad mileage in her 2003. I don't know if these cars get bad mileage in general but I'm changing her air filter and tossing in some Valvoline Fuel System cleaner to see if things improve.

 

Yeap, just got a used 2000SE and got 13.3mpg on my first tank. Called up Autozone and the mechanic answered "holy crap" on the phone. Almost makes me hope that there is an O2 sensor dead or something which will drastically improve gas mileage. Otherwise, I'll be reselling this car within a year

 

hell averaged 14 mpg today.
just tried to test last time filled yesterday three warm up's (each 5 min) so i think it's greatly effects your economy

 

He said he did. Inflate your tires....

 

this is in response to phillymax saying that because of winter the car is running richer. Running rich means that the air to fuel ratio is lower (more fuel than air) than the recommended 14.7 to 1 air to fuel ratio. Picture this, when you are running in the summer you get out of breathe quicker than in the winter because the summer air is not as heavy. Winter air is denser. The denser the air the heavier it is. in essence in the farthest possible since the denser air acts to force itself in the engine verse the summer were it is less dense or heavy. the more air in the engine is read by the computer which will up the fuel going in to try and keep the optimal air-fuel ratio thereby making it eat more gas. I have a 68 camaro also that is a dog in the hot hot sun but on a nice night or spring or fall day is a beast. Both of my boys are naturally aspirated and a difference is definately felt. also run premium gas on them both and a def difference. Never would use 87 unless i had a Honda. haahaha

 

go for the High Grade 93 or whatever you can get. ECU is set for 91 oct so give it what it wants. Also slow the **** down, you gotta be giving it hell. I got a 2001 engine in 97 with no emission or any vuccum sensors hooked up. I got 25 mpg on like 70% highway.This is just last weekend so im thinking its still winter gas??? I sure with egr and evap i would pick up 1 or 2 mpg maybe. Im not so sure those really do a whole lot but they might. I got 18 mpg on my city tank and it was first week out so i beat it good!

 

It was 70 degrees out 2 weeks ago her in Philly for about 5 days, and I averaged about 25 mpg. It has since dropped back down to the 40's and now I'm only getting about 21 mpg. I guess my engine favors the warmer temperatures.