Man, it's stories like that which make me consider replacing my 7-year-old MAF now, instead of when it (eventually) craps out.

If someone could identify the IAT sensor as a direct purchase (radio shack), I'd probably buy the 2001 MAF and just do it.

 

269! wow.. what did you put down for tq?.....make a post in the dyno section with your files if you have them


and thats a great idea about swapping maf's.. simple and effective..

 

269whp 260wtq when it was 235whp it put down 229tq i would like to someday put down the 278whp jaypee is putting down that would be awesome I'll see if i can get the file from the last dynojet...i doubt it though but i'm going to swap in a hlsd so i'll re-dyno then i'll post my #'s then i'm just happy i found the problem and it was the maf and it only cost me 90 bucks, doing all the crap before that like the coil packs just gives me piece of mind now. It will be interesting for the next dyno since I have had the custom reflash from technosquare, and ordered a velocity stack, it is put away for the winter but i will dyno in the spring. BTW i have 117k mi just broken in...lol.

 

i just swapped mine from my old one, worked beautifully.

 

When i drove from OKC to Phx last month, I got 27.8 mpg over 930 miles and rain all through Texas on I-40. On the way back, Phx to OKC, I got 28.4 mpg taking the same route, no rain.
105k, '03 SE, Auto

 

appreciate the advice guys...its given me a well rounded approach to figuring out what the heck is going on...

looks like i need a tune up, check psi, check air filter, and possibly check MAF to start...i will get back to you when I do this and let you know what i find out.

however, regardless of mpg, i will agree, having 2 maxs' to choose from is an excellent problem to have...they both kick a** 100% of the time! :

http://twitpic.com/ivko9
hers. his.

 

Same boat here, gas mileage has always been crappy since I bought the car. When I bought it, I noticed the slight hesitation but thought nothing of it and figured it was something a tune-up could take care of.

After getting the car and joining this forum, I knew it was the MAF. My mileage has gotten even worse because up here in PA, I believe they switched over to the winter gas where the add more additives and stuff. I'm getting 250 miles to the tank and that is with regular driving and nothing ridiculous. I think I'm going to do the 2k1 MAF swap. For the money, you can't beat that. I'd rather have the AM600 MAF but I don't want to pay that price for it.

I felt my car dynoed a little low and I think this could be the cause of it. Thanks for all of the info in this thread.

 

Your not alone, my car has been averaging 250 miles in a tank of 93 shell gas. I even threw in a bottle of bg44k and nothing happened

 

I use 93 as well. I thought it might have been the tune I have. It does run a little rich on the low end, but still, on the highway, I should get better than 22mpg.

 

I have an 01 and a 5 spd with the original MAF not quite the 250 range but usually getting 270- 290 range with 92 shell octane usually. The car isn't showing a check engine light or anything but might be time to get a new MAF or try cleaning mine. I've had some heavy 20" wheels on for awhile though and I'm sure that has contributed to some of the lower gas mileage. Just got a smokin deal on some 18's with tires that I'll be using for a winter setup so I'll be curious to see the difference.

 

i am very curious to how much exhaust leaks play a part in gas mileage ?

my flex pipe has been leaking 6 months now.

 

I think my gas station may have switched to the winter-mix gas as well. I went from 390 miles before filling up again, down to about 315.

 

Going to preface this by admitting I hardly read every post in this thread, and didn't even look at page 2.

I hate gas mileage threads, mostly because of how wrong most people have it.

If you think your gas mileage is low:

Pressure in the tires is probably most important, gas-robbing thing. I agree, the mileage is a bit low, but not THAT low (cruising at 80 burns gas, see what you get cruising at 70).

The 6 speed should and will get better gas mileage. This is due in small part to the gearing advantages, much larger part due to the efficiency differences between a flywheel and a torque converter.

Also, you should feel the RPMS drop 4 times from a standstill, not 3:

First drop: 1-2 shift
Second drop: 2-3 shift
Third drop: 3-4 shift
Fourth drop: converter lock

If you're only feeling the RPMS drop 3 times, something isn't happening in that process. Also will rob gas.


Good luck.

 

i do 100% city driving since im in college. plus i think gas stations have put ethanol back in their gas.

i drive with v-power and get about 250 miles per fill up as well. i avg 17.4 mpg which is close enough to the rated 18mpg city so i doubt anything is amiss.

 

So I started looking at what EPA for a Maxima is and I have seen anything from 26-28 highway, and 18 city.
Now if I drive heavily city I get about 19, but if I drive highway a lot I get just under 22mpg(21.8). I go around 80MPH.
Would the gas mileage really drop almost 6 mpg by going 80?
Also what can I do to get my mileage back up? I changed spark plugs, inflated tires properly, I'm running a cold air now, I try not to go above 3000 RPM before shifting. I really could use the help. I need the increased gas mileage. College is damn expensive.

 

headers I get about 25-26 hwy

 

Holy resurection cow - what have you done!?

In any case, Driving habit, Driving habit, Driving habit.
I can sit here and list tons of mods and options to aid fuel economy, but those are going to cost- which is money you say you don't have.
Keeping it basic; Simplest and easiest things
are maintenance and car care, reduced speed and limited idle periods. Use 5w40 oil on changes and run ethonal free gas.

 

See that's the thing. I started looking at the RPM's at various speeds. The difference in RPM's is no more then 600 from 70 to 80 miles per hour. I live outside of Atlanta and the Speed limit is 70mph. I can't do 60mph without almost being run over by a jacked up Ford. I am trying to understand if there could be some sort of mechanical issue that is causing such a decrease in gas mileage. I always shift before 3000 RPM's, coast as much as possible, and try to stay at a constant speed. Yet I am still barely able to get about 22 mpg. My parents Honda's can do 80mph and still get 25mpg if not more and they are bigger engines.
I guess the main question is; Is the gas mileage really going to go down almost 4-6mpg when I am going 80mph verse what ever the epa tests at?
Also how will using 5W 40 help verse 5W 30?

 

http://www.mpgforspeed.com/

 

I understand that the increased speed will decrease my mileage, however I have friends with honda's who can go 80 and still get 25mpg, and even other friends with maxima's that get up to 28mpg doing 80 mph. (they are all automatics, I drive a 5 speed)

 

Don't compare honda to maxima. You're comparing rotted squirrel turds to apples here.

If they ain't measuring MPG BY HAND then it don't matter, first off. Miles driven by gallons filled. NO OTHER WAY. Not even by trusting the onboard computer.

Unless your maxima friends have the exact same ssetup as you do, use the exact same fuel as you do, and weigh the exact same as yours does, the numbers will be off. If you have a sub, amp, and a couple passemgers in your car you will not get the same mileage as your loner friend who drives by himself all stock.

What "upgrades" do you have? How well is your car maintained? Do you use premium gas? on and on and on and on and on.....

 

I forget the hatred that the .org guys hold for Honda. And to answer your questions.
All the gas mileages I have quoted have been done by taking a full tank of gas, recording the miles driven then divided by the gallons of gas added back in.

 

LOL I don't hate hondas, I'm just feeding into it. My first car was a 86 Accord.

83 octane? Never heard of it that low...lowest around here is 87. But anyhow...based off MY personal experience with my car...when I bought the car I used 87 (same as original owner did) for two fillups and noticed about 16 MPG. Then I used one can of seafoam in the car and one tank regular, got 17 mpg that time. Been using Premium ever since and consitently get 20MPG. No change in driving habits (mainly city) whatsoever.

Your system could effect the mileage, sure...even though it's only a 10" sub, absolutely! If you increase the load on the motor, it will have to work harder to do what you want. engine working harder = less MPG.

I bet that the other cars in your family (Acura and minivan) are not driven the same way yours is, am I right? Also, is your car in tip-top shape? Current tune-up and all that good stuff? Read up and find the recommended replacement intervals for plugs/o2 sensors/fuel filter...have you ever changed it? If it has been more than, say, 50k miles since you replaced the fuel filter, do it now and come back after a couple tank fuls. Run injector cleaner in your engine as well...clean engines run happier. What about tires? overinflation / underinflation affects MPG as well...

Basically, there are about as many reasons for "poor" mpg as there are stars in the sky.

 

I haven't heard of 83 either. Just a typo. lol
All the cars are drive the same, to be honest mine is probably drive the least rough. I am slow off the line, shift early and do a lot of neutral coasting.
Spark plugs have less then 2000 miles on them, oil has just been done, O2 sensors are not replaced except for one. (I was unaware that you are to replace the sensors. The one I did was very expensive and a horrible pain to do.)
Everything I have been told about the fuel filter is do not replace it unless your replacing the pump to. According to the Nissan dealers the filter is a lifetime filter. Plus, idk how if I could replace it easily and at what cost?

 

youre 5th gen, eh? your filter is not teh same as mine...nvm. I'd personally do it though.

front O2 sensor has greatest effect on gas mileage (bank 1 sensor 1, I think)...I swapped that out on my Pontiac last year and got 15% better economy right off the bat.

 

Yep I drive a 2000 max SE 5 Speed. Its supposed to be a lifetime filter. From what I have heard to replace it is a very tricky process. Its so complicated.
I replaced the one pre cat I wanna say. I have to double check my records.

 

What Will using 5w40 do for my car compared to the recommended 5w30 that the car is supposed to use?