I went out for a long drive yesteday, about 140 miles and had the cruise control on at 68mph the whole trip and I still managed to use up nearly 1/2 of a tank of gas. Something does not seem right. Right now I have just hit 50,000 miles. Just cleaned my air filter about 3k miles ago, changed the engine oil last month with sysnthtic 5w30 and tires are inflated to spec. What are some things I need to change/ replace at 50k mles to improve my gas mileage?

 

Spark plugs... Changed mine at 60k and they were TOAST.

 

So.....
is your actual mileage(MPG = M/G, where M = Miles which is reset after you fill up your tank, and G = gallons actually read from the pump where you filled )?

 

havent calculated the actual mileage but the trip computer say that its at 29 mpg throughout that trip. But we all know how inacurate that is!

 

Mine has read in the 80's ...

 

So I'll probably have to change the spark plugs huh??? I'll probably pick up a set of NGK coppers. btw, are the coppers what nissan used as oem?

 

Nissan used Pt's, but I repalced them w/ Cu's.

 

what type of gas? use at least 91 no ethanol. if you use 87, you will notice slightly worse gas mileage.

 

I am no expert but i have a 03 GLE and have the same problem. I was told my friend that the reason for the bad gas mileage was the idle air valve was not functioning properly not necessarily the spark plugs or type of gas (although those may have something to do with it).

 

it could be a whole number of things. and honestly for half a tank getting around 160 miles isn't too bad. are you automatic or manual? I do stop and go driving around my town and usually end up getting 250-300 miles for the entire tank; which is good for a 6 cylinder. My old 4 cylinder altima would get around 250-300 on a tank of gas but when I took that on to the highway for long trips I got around 420 miles on a full tank. Make sure your cars alignment is also good

 

Everything stated refer to this---> depends on the size of the tank ...

 

5.5 gens have no IACV, we have e-throttle or drive-by-wire as nissan calls it.




As to the original post, like someone mentioned already, there is a plethora of suspects involved with a change in gas mileage. Most of the common ones were already mentioned, but there's really nothing else you can do but guess and check...I would just do the routine maintenence and see what happens.

 

I get roughly 22 mpg in mixed driving just to make sure, when you're using your cruise control you're not using it on hilly/windy roads right? In those situations using cc will actually worsen mileage because the computer is constantly trying to maintain that constant speed.

 

Why do ppl refer to their gas mileage in terms of miles/tank and not miles/gallon? Lets all use a standard. Miles and gallons are constant around the world....so lets use that.

 

So what do you do.. Climb the hill like a granny?


You sure about that? What about liters and kilometers?

Canadians use it, as well as Europe.

 

I live in a hilly area, use my cruise control a lot and get over 200 miles per 1/2 a tank.

I changed my plugs at 100k and they weren't that bad but, every car is different. I would at least check the front ones. o2 sensors? MAF?

 

A mile is a mile no matter where you go. Same with a gallon. We use liters here and run the 5K...10K....etc. I'm not talking about what others use...I'm saying that a gallon is a gallon. Not all tanks are the same size.

 

colder weather+winter gas

 

I vote for the O2 sensor.

 

yah because the united states and one other country are the only countries in the entire world to use miles and gallons. everyone else uses the metric system.

 

the difference between my altima gas tank and the maximas was I think only 2 gallons.

 

his point was that miles per GALLON is a much better represention of fuel economy than miles per TANK. For example, sometimes my car says it's empty and then it only takes 15 gallons to fill up. The very next time i fill up it could take 17 gallons, it just depends on the fuel gauge. 2 gallons is 50-60 miles or 2-3 mpg when you get 400 miles out of a tank, which is definitely considerable when talking about fuel economy...

 

sounds a bit off.... When i cruise around town i can keep 320-350 to a tank. Only thing i did recently was plugs, and that was just because i felt a bit of a power loss, mileage was still good. I do have a pretty light foot.. maybe thats the problem

 

in one word? yes.

 

Were all the variables the same? The weather is nicer now, were you cruising with the windows down? Extra junk in the trunk? Was it windy that day? Were you out in the open vs tailing someone?

Then there is the whole winter gas theory. It is about time for those arguments.

In this forum miles per tank is just out of ease. Ignoring the obvious difference between the 5 vs 5.5 we all have the same engine, tank size, etc. You are correct though it isn't as accurate, but doesn't require any effort either. There will be a difference in the person who tops a tank vs stops for the click. I think a lot of people get caught up in the absolute numbers vs whether they are close to the reported average between members.

 

Untrue.

1 US gallon = 3.785 liters = 0.8237 imperial gallons

We mostly use L/100km in Canada but still often refer to miles per gallon (especially older folks). When we do miles / gallon, we do miles per IMPERIAL gallon which is obviously different than miles / US gallon.

I do, however, agree with you that it makes more sense to talk miles per gallon than miles per tank.

 

I stand corrected

 

I just got 15% better gas (fuel) mileage because of light weight wheels.

 

mine seems like it gets ****ty gas milage too. Theres gotta be something wrong with it. Im at 56,000 miles and probably in need of a minor tune-up. I filled up the other day with over 40 buks in gas and its half way gone. I dont remember even really going anywhere. The dash always stays stuck at 22.5 or 22.7mpg so I know thats bull****. I might change the plugs but even if there bad I dont think its gonna make that much of a difference in mileage. If a sensor was bad would the car throw codes??

 

Mine is bad too.

Suspecting its the o2 sensor.

Filled up last weekend, and do almost all city driving (12 miles per day, city driving) and i'm at 1/4 tank left (towards the empty side) and only did 122 miles!

Something is definatly wrong, and I think I'll start by checking my plugs.

 

122 miles driven and you are already at a quarter tank... Damn...
I'm *****ing and griping cause I'm at 268 and at a quarter tank. More highway than city, but the highway is Ups and Downs and LOTS of curves. So its not a good measure.

When I bought the car 4 months ago. I was getting 21-22mpg for the first three/four tanks. The last 2 - 3 tanks have been late teens. Same driving.
Something changed. I doubt plugs, not at 53k. Plus our plugs are suppose to be good for 100k. o2 maybe. But no codes...

I hate this. Getting almost same mileage as my old Truck in a car with a smaller engine and lightweight. The pathfinder use to give me 14-15mpg religiously. Max is seeming to gonna be 18-19 regiously. I expected low 20's. Not high teens.

 

yea mines suck. There's a thread somewhere about NYC owners posting their MPG and mines seems very similar to theirs. After reading that thread, i'm not too worried as before. It still sucks though.

 

maxima gas milage sucks, ive been getting 20 mpg and i accelerate slow as hell, hwy/city mixed. if i drive any faster my milage gets worse. nissan isnt great at gas milage, acura TLs get around 29 mpg on the highway.

 

Mine doesn't suck. I can get 25 mpg even doing a few WOT bursts on the highway. I have gone as high as 27 mpg.