I've noticed in this forum there are few conversations about MPG averages. I'm curious what other people are getting, and thought starting a thread for comparing would be helpful for other people to know the condition of their vehicle.

Just keep in mind that if you post, folks may assume your rig is stock, but if you've added forced induction, or changed out the exhaust, or modified the intake, that'll change the numbers for best or worst.

This website will allow you to check what the EPA estimated mileage is for your vehicle.

I tend to average 24 mpg with mixed driving and have gotten 28 mpg with mainly highway driving. I've not done anything drastic other than replacing the muffler with a glass pack, did a ghetto air box hack by punching a hole in it, and inflated the tires to 50 psi for lower rolling resistance.

For ideas on improving fuel mileage, check out ecomodder.com. Lots of people there with good common sense ideas.

 

87 octane?! you're nuts...

 

1999 Cali Spec. Nissan Maxima very well maintain with OEM Fed Spec. headers and y-pipe, high-flow catalytic converter, budget b-pipe, and OEM muffler. Light weight 18" wheels and dropped suspension (closer to the ground and cuts through air better I assume, even if it's just an inch). No other mods.

100,000 miles

 

99 5 speed
170,000 miles
90% highway driving
Can never quite top 30 mpg

Oh ya, 87 octane

 

When I moved cross country my wife drafted my enclosed cargo trailer in our Max for 1200 miles and got up to 47 mpg!

 

i feel bad,i put 6.2 gallons in and got 86miles from it,abt 13mpg
the fill up b4 tht..i put 6.4 gallons..got like 110,worked out to be 18mpg...

 

my 99 i30 avgs around 22 mpg w/ 30% highway / 70% city

149k miles in it and everything is stock; 87 fuel but might soon switch to 91

 

99, Auto, Stock, Basic Maintenence.
Crusing at 75-80 I get just under 30 mpg on a trip.

 

How are you averaging so high!?!?! Im not even doing 21! If I could do this I wouldnt have to thinki about getting a 2010 maxima! XD

 

my max has 243,000 Auto. My last trip up to Pittsburgh, I was getting 28.2. That is with 2 people and a whole lot of luggage in trunk. Average speed was 75. Just keep up with maint and such. Always use 93

 

340-350 miles per tank (21-22 MPG) in Atl suburbs. '98 SE

 

i use to average about 380-400mi (25-26 mpg)per full tank on 93 octane, but now i average out no more than 350 for some reason. ineed to change my plugs and hopefully when i do i'll get better mpg's...

 

Do most of ya'll use high octane? I'd never tried using higher octane in the max to improve mileage, but everyone seems to be doing well on it.

 

Where do you get the graphics for your fuel economy chart? Very nice and tidy and looks to be very thorough

 

My wife's 96 GLE on the interstate running from 65 to 75 has averaged as high as 32 on 87 octane, My 95 probably gets 22 mixed and maybe 25 on the highway. Her car has about 280k, but I put an Infinity engine in several years ago when I got the car that had 58K.

 

I'd be curious to hear more details about the Infinity engine you put in. does it have more sophistication allowing the better economy?

 

i use 93 octane, oovi and full exhaust 2.5" with 16" lo profile tires at 45psi. about 460 a tank. so 28-30 mpg avg?

 

I do not believe the high mpg numbers quoted here. I hope everybody understands the size of the 4th gen fuel tank, it is not 15 gallons! What is it 18 or 19 gallons? And i hope everybody is doing the simple division correctly, also taking into account any leftover gas from a previous fill up when resetting the trip meter at a fill up. And please no kilometers. Lets get real numbers on this thread this time so we aren't fooling ourselves, basking in contentment and stoking the envy of others with erroneously inflated numbers, if that is the case.

 

I only see one number that seems a little far fetched. 47MPG, Im not gonna say its not possible. But still....little high.

'95, Auto, Stock, ~235,000 Miles
I average(50% City/50% Highway) 24.4MPG. On a few trips to MO and TN I have been able to achieve a nice 30-31MPG on the highway at around 75-80MPH. I only use 91 octane(higher when I can get it)

 

Some may be making mistakes, but I know for a fact that I can get 29+ on the freeway averaging 70 if I take it easy on the pedal. Personal best was nearly 31, forgot the exact number.

I measured by filling it to the rim, starting the trip, then filling the tank back up to the rim and calculated the mileage to 1/1000th of a gallon. As if gas stations' meters are that accurate, they aren't mind you. BTW, 150K on the car and using 91.

 

How fast were you going and how close was she to trailer?

 

i use chevron every so often so i get 27-30 mpg hwy. Depends how much i feel like passing other drivers hehe

 

I wouldn't doubt the numbers too much. On my best trip I did drive a bit more aggressively than I should have yet still managed to eek out a solid 28 mpg. I even did a bit of showing off with my father in law, so 30 mpg is definitely a strong possibility.

And the lady tailgating the cargo trailer could easily have gotten those numbers. Aero drag is the most important factor causing fuel consumption at higher speeds. In fact, aero drag quadruples when you double your speed. That's a figure that can really eat your lunch. And since they were moving, I'd expect she was around 55-65 mph and may have run nearly nonstop for the whole tank. I wasn't suprised too much to read about her 45 mpg tank.

But in all fairness, make sure you're posting good average figures that have been figured to the best accuracy possible. That'll make this thread continue to be interesting and informative.

 

does chevron have better gas? We don't have it out here, but i do prefer shell for my fill ups

 

It's true that some may be miscalculating their MPG's. But, I have been calculating mine for several years now, using the same method and filling up at the same gas station. It's always been between 27-31 MPG, which would be an average of 29 MPG as a DD. 50% freeway smooth sailing and 50% heavy gridlock.

So yeah I believe when people state that they can get around 30 MPG also.

 

So true. However, that goes for virtually anybody on the road, not just Maxima guys. 99.9% of people, even otherwise car-savvy people, either have no idea how to calculate MPG or do it improperly.

Personally, I fill up at the EXACT same pump at the exact same station 99% of the time. The only time I don't is if I'm stuck out somewhere low on gas and can't. I also only use Chevron or Shell (both are top tier).

I don't doubt 4th gens can get 30ish all hwy, though. My VE's get 30 mpg hwy. I usually average about 24 mpg with a mix of city/hwy driving.

 

Wow guys, I never thought about this my car gets ****Y gas milege like 15MPG. every since i bought it i put like 15,000 miles on it and did notice i fill up quite often. it has a bad knock sensor and crank shaft position sensor. it cost $42 to fill up at chevron and thats the ONLY gas i run and its 87 octane anyways i got 292 miles out FULL tank of gas thats all city. it runs perfect smooth is hell and powerfull its automatic with 280k miles and i was braggen to my brother dam i never got this many miles to my full tank of gas. and now i see u guys getting 350 miles out a tank and thats only 22MPG??? DAAANNNNGGG. i should of thought about this years ago its a HUGE tank and is gone like a small tank is!

what could be causing bad gas milege on my ride? im soft on the gas most the times and has full tune up new oil everythings perfect on it. i doubt a knock sensor or crank sensor would cause this cause theirs no miss fires.


Thanks if any reply back to me. now im worried,.

 

I get about 35.30mpg on my 96. Its mainly highway 236,000 miles AEM Short ram, OBX R muffler, and 19in Rims on low pros.

 

You guys need to remember that bigger wheels throws off our speedometers and odometers

I read about it when I thinking about going with 19in wheels, which would be larger than the overall stock wheel size.

 

Not always, depends on the tire size for the larger diameter wheel. In general, There is a small decrease/increase as you say. But it's dependent on diameter, cross sectional area and aspect ratio.

 

From what others are saying, a bad knock sensor will throw off your mileage, since the computer will be constantly retarding the ignition, throwing off your mileage. As far as the camshaft sensor, I'm not sure, but it could be hurting as well. If you want your computer to know what's up, it needs good info.

Have you kept up on the maintenance on the tranny as well? My car had 198k when I bought it, and not knowing the maintenance history (and considering the oil was pretty dark) I changed out the tranny oil. Might not be a bad idea if it hasn't been done in a while. Nice thing it, our transaxles (or at least mine) has a drain plug for a poor man's change.

And changing the size of your tires isn't going to affect the tachometer, only the speedometer. The tach is going to read exactly the same no matter what size tires you put on.

 

Since august of 09 ive averaged 24 or so. But ive gotten anywhere from 18 to 31 within that span. New knock sensor seems to have helped that number stay a little more consistent though. Its all a mix of highway and city too. about 50 miles a day

 

umm idk about you guys but it really doesnt matter how i drive my car i always get 23-25 MPG's.... if i drag race it, or if i drive like a chick it seems to get over 415+ miles on a full tank of gas til the gas light comes on

o and those fuel cleaner things dont help out at all, stayed about the same, maybe like 5-10 extra miles on the tank.... havent tried seafoam thing yet though

99 SE 149,817 miles
30% highway 10% traffic 60% normal roads
85 gas
colorado

P.S. Where do you get 93??? seems like everyone uses it but never seen it, and is it really better? or just cleaner?

 

05' 87K miles...97 Octane..about 22 city and 26 Hwy...

 

My bought new in 95. varies a bit. but here is this years records.
only mods are Y pipe Hi-flow cat and Stillen CAI.
normal Maintenance schedule is followed. .
50/50 city Highway and a very heavy lead foot.
91 is the highest available here in Salt lake city.

 

In Colorado, you're 6000+ feet above sea level which changes things a bit. 85 octane in Colorado performs the same as 87 below 6000 feet. So putting 91 octane in your tank would be the same as putting 93 octane below 6k feet. Nice thing is you could put in a bit more of an aggressive turbo on than we could due to the lower air pressure up there. But as stock, you're car wouldn't put down all the horses it can at sea level.

And the higher octanes are about the same, just that they don't preignite as easily. Using 87 you'll occassionally hear a small pinging sound, especially on a hot engine, which the computer adjusts for with a bit of loss of performance. Putting higher octane allows the engine to run a bit more normally.

When it comes to getting higher MPG, it comes down to the nut behind the wheel. Oftentimes, simply driving less aggressively, running the speed limit instead of a bit over, and keeping up with your maintenance can increase your MPG more than anything else, other than aggressive reconfiguring of your vehicle.

If you set your mind to increasing your mpg, you'll be suprised what your Max can do on a gallon. But she needs you to do it, otherwise she'll just do as you tell her to, which is burn more fuel.

One of the first things I would check is your tire pressure. Contrary to popular belief, you can increase the psi in your tires safely to 45-50 psi with no side effects on pavement. Just going to 50 psi can give you an increase of 5% in fuel economy, but sometimes it can be higher.

 

I have a 99 max with 130,000 miles.
Only thing done is cold air intake and my car has a bad o2 sensor that is making my air/fuel ratio too lean

I have been getting 21-22 mpg with 87 oct.
I have filled it up a couple days ago with 92 oct and it seems to be getting better mpg, will post what I got for mpg later

 

i have a 99 se loaded (maybe that ways more idk.) im averagin about 21 mpg only city with really stupid long lights. im really not exactlly "nice" to my baby but she loves it. i only use shell 93 octane everytime i fill up i reset the trip and ride until the low fuel light illuminates then it straight to the shell. then i take the miles i went and divide that by the gallons pumped it seems to be pretty accurate. let me know if you know any better ways im always up for new ideas.



p.s. injen cai, magnaflow headers/ y-pipe/ and cat back, and a 3 deg. timing advance. (202k miles)

 

A bad o2 sensor is supposed to make your mixture too rich IIRC. The theory is running lean will burn up the engine, so better to run too rich and just burn more fuel.

My 98 SE is also loaded to the gills, but adding 100 lbs only decreases your MPG by 1 mpg sometimes. And all the options you would have simply displaced what was stock, likely netting little to no gain in weight from stock. Your method for checking your mileage seems to be spot on. You'll have variations sometimes, but if you're quoting the average of all your fill ups then you're probably correct.

Looking at your mods, sounds like you've likely added a couple hp from stock and you like to use it. Drive the old girl like a granny for a week and you may be shocked at the mileage she'll get. Keep the rpms under say 3500, stay at the speed limit, and try to stay in top gear when climbing a hill, which sometimes means slowing down temporarily til you crest the hill. I managed 28 mpg drving like that for most of a tank and it suprised the daylights out of me.

2 questions. Do all Maxs have a low fuel light? I fill ours once a week and rarely go below 1/4 tank, but never have seen a low fuel light. And how do you adjust the timing? It's controlled electronically, so is there and adjustable sensor?

 

luckilly for me i have a friend that works for nissan the only way i know to do it is to plug the consult2 scantool into it since it manufacturer specific you can do all kinds of cool stuff like roll your windows up and down and manually shift your auto tranny and of course adjust your base timing. and the low fuel light i would assume that its a standard feature but mine at least comes on when the gauge reads real low like "your gonna be pushin low"