I have a 2003 SE Auto with 2800 miles on it. I just took an 800 mile trip with it and only got 22 MPG. My average speed is 80, but my wife's 1995 Max gets 25-27 in the same conditions. Is this normal? What are some of your experiences with gas mileage improving with age?

 

my mpg range anywhere from 17-22

 

Sounds right, my 2k3 does about 19-20mpg now. I always thought it funny how 80mph is right in the middle of the speedometer, its like nissan is "suggesting" that speed. Anyway, do a search, tons of threads on mpg.

 

ive found that cruise control and cruising speed make a big difference with gas mileage on this car. i normally cruise at about 75-80 but that didnt yield very good MPG. i usually got about 22 or 23 MPG. so ive taken it down to about 69-71 MPH and set the cruise control there and my mileage has improved dramatically. on saturday i just got 29.7 MPG (computer said 35.8)on a 130 mile trip from school to home with an actual cruising speed of 69 MPH (computer said 66 MPH).

so two things:
80 MPH is a little too fast in thsi car if you're worried about good MPG. my 96 Maxima got pretty good mileage at that speed but not the new one.

and...

the computers in our cars are pretty inaccurate.


also, note that in this whole post i was talking about highway trips. my around town MPG is REALLY bad here at school. i just filled up before i went home and got 11 MPG. but usually i get around 19 MPG around town at home.

 

I agree take it down to at least 75 and check it again.
I get 19-20 in the city and have gotten 29 on the highway.

03 SE 6-speed

 

I only get about 18-19 mpg also in a Mix(city/Hwy) in the Max and well as in the 350. In both cars the computers are off, the 3.5 just drinks alot of gas( alot more than the 3.0 in the 95-01's) and when you really step into I see that gas needle dwindle in both!

 

I've been getting poor mileage on my 2K3 too. I've tried different gas stations but the result is the same, around 17 - 20 mpg. My previous '98 SE would average about 22 mpg. I'm hoping the mileage will go up when the stations here in NY switch back to non-oxygenated ("winter mix") gasoline.

 

Our 2k 3.0/auto gets 21-22 MPG in town with her driving. When I drive alot it is usually worse. Over the weekend we took a trip up to Holmes County to do so furniture shopping (nothing like Amish made furniture). Almost 300 miles, of that about 80 were on I-71 and the rest was driving was stop and go, under 60 MPH and quite a bit was with O/D off since we were in some rolling hills and it was in and out of O/D all the time. That tank netted us 22. Not quite as good as the 99 SE Auto this car replaced but I can live with it.

T

 

I just had to fill up this morning. With mostly city driving i got 20.6 mpg. Not to bad for stop and go. All i'm worried about is how much higher the price is going. $1.84 a gallon here.

 

From my expereince, I get the best balance of speed v. MPG at around 70. Milageage really starts to take a hit after 70.

I average 22 MPG with my 2k3 6 speed with about 70% highway 30% city.

The computer says 26-27, like everyone else, that thing is about 4 MPG off.

The difference you are seeing from your Wife's 95 is the price you are paying for more HP.

-Steve
'03 6 speed, HLSD

 

im getting 260 miles per tank according to the comp. i paid $1.99 last night its ridiculas.

 

You can thank our Pres and Big Oil. Wait until the war hits and you pay over $2 a gallon.

 

I bought my '03SE a week ago so don't quite have the stats. I have been told using the heater or A/C will worsen the mileage. Is this true? Also will Octane 89 or 91 affect the mileage? Has anyone use Octane 89 or do I have to use 91 as recommended?

 

Is it recommended to use 91? (!!) Where is that, in the manual?

using the A/C will worsen mileage due to the use of the additional belt driving the compressor (it makes the engine work harder). Using the heater shouldn't be the case, since the air is passed through the heater core.

 

I have not finished reading the manuals yet, the Octone 91 info came from the dealer. Are you using the 89? thx

 

I haven't filled my tank yet... will be doing so on Sat morning... however, I plan on using 89 all the time (unless otherwise told). There isn't a HUGE difference between 89 and 91.

 

Fuel recommendations are on page 9-3.

 

WE have ALWAYS used a min of 91 (in the 99 and the 2k) but most of the time it is 92 or 93. I know what a diff premium makes in my truck (believe it or not) so I can only guess/imagine how much difference it would make in the car. No chances for me... good stuff all the time!

 

There have been a few threads about how the knock sensor will seriously retard timing with 89, thereby killing your HP

My gas mileage on my 2k3 has dropped as far as 15 (real mileage, not Max computer), and even on a straight highway run the best was about 22. Interesting comments about the dramatic difference in mileage between 70 and 80+; wonder if the computer changes mixture or timing etc. between those RPM ranges?

 

My 03 Max was getting terrible gas mileage after i did my mods..it was like 17 city...then i disconnected the battery for an hour and drove it in the city and now im getting around 19/20...im not a highway driver too many rocks to damage the pretty front end.

 

It's due to air friction. The % difference is most significant when you go from, say, 55 to 80mph. That's why if you look at online recommendations for gas saving (I think I saw something like this on AAA site, and when an online warranty broker sent me "10 Tips to driving" or something like that), they also mentioned that 55-60mph is optimal for highway mileage.

 

Hmmm - could be, but from what I've read (I'm a cyclist, wind resistance is important to us ) the drag would just continue to increase. There's no magic 55 - 85 change.

There could be enough increased resistance beyond 70, I guess (wind resistance doesn't just increase, it doubles at pretty small speed increases), but my '95 got WAY better mileage crusing at 80+.

 

but remember also that your 95 had a 3.0 litre engine, not 3.5. larger engines eat up more gas.

 

My former vehicle was a Dodge Intrepid... a '97 with the 3.5L as well... I know it was designed a bit different... with a stock 215HP (I was running around 250HP after mods)... but my old 3.5 used to get an average 360 miles for 17 gallons in the city (21mpg) and 460 miles for 17 gallons on the highway (27).

So I hope the Maxima will get at least an average of 23 or 24.

 

Sure - but I'm wondering if it's the 3k+ rpm range where the ECU starts altering timing etc. so there's a noticeable mileage drop. But, as you say, maybe the tuned and larger 3.5 just eats more gas. It's fast though

 

I just happened to find this website & started reading, I am loving all the info. I just traded in '98 SE for a new '03 SE (titanium package w/ leather) two weeks ago. I was thinking I would get better gas mileage w/ new max (rated 20/26) vs. my '98. I have been watching the MPG read-out thinking I was doing great. Then I started reading forums & seen people complaing about gas mileage, so I went & filled-up last nite. Man, I am ticked-off!!!! Stupid MPG read-out was telling me I am getting 22.4mpg in the city, but I am actually getting 18.9mpg.

Guys, I am talking about break-in driving, no fast take-offs, maybe hit 4K rpms twice, usually 3-3.5K rpms at the most. What in the world is up w/ that? How in the world can the computer be off by 3.5mpg???? W/ gas at $1.70 (mid-grade), 3.5mpg can make a big difference on a full tank of gas.

Please any suggestions. I know the engine has to loosen-up & I might get better mileage, but how do u explain the computer being-off 3.5mpg? (hate to think might happen when I do put my foot into it) Do I need to bring it back to the dealership or is that a waste of time? Any suggestions appreciated, thanks.

 

So I went last night and check the manual... and, indeed, on page 9-3 are the fuel and lubricant recommendations. It says to use 91 octane... but then if you read more and turn the page, it says to use between 87 to 92 octane and talks about if you use less than 87 AKI (for example, some areas offer 85) it can result in knocks, etc.

So this is hinting more to what I said... it doesn't hurt the vehicle to use a constant 89 octane, which has been proven to give your car the best MPG. I got the best MPG when I used 89 with my Intrepid, I will test the same with this Max.

-R

 

Uh, by whom??

Any documented tests?

 

I just wanted to give everyone an update on my Max with bad mileage. I decided to test the mileage with higher air pressure (38.5 VS 32 psi), and at 60 MPH (vs 80). I did a 43 mile test run and I did 37 MPG trip computer, 33.5 actual. Not bad. My next test will be at 70 MPH. If I can get 28 MPG, I'll be happy. I'll keep you guys posted.