Okay I did not want to make a thread about poor gas mileage but this has become ridiculous. Recently I started checking my mpg on a full tank ... which turned out to be 260miles on a FULL tank. Yes all 260 was local and if you calculate that ... that is 14.4 mpg (260/18) The other week I took a 150 miles round trip to Jersey and that tank was about 310. Turned out to be 19.375 (310/16) From what I have seen on some threads, driving skills and road condition plays a part in your mileage. However, I drive exactly 60mph on highway (2rpm) and on local streets my rpm meter stays between 2-3k. I cleaned my MAF 2-3 weeks ago, tire pressure is good, and I use 87 octane gas from Sunoco. The only thing I haven't tried is Sea foaming but I recalled reading a thread somewhere about having side effects on your car. Also I am planning to run fuel injector cleaner but Im not sure which brand. Maybe a tuneup as well? ... not sure if it will help

Is there any other ways to improve my gas mileage? My friend bought an Evo X and he gets like 300ish miles on a tank ...

Edit:: 2000 Maxima Se Auto with almost 102k, sorry I was way too sleepy when I made this thread.

 

I had a similar problem over the last month or so. I had thrown a code for MAF, so I cleaned it and reset the computer and I am finally getting my mileage back up to around 23-24 mpg. Most of my mileage is city and I'm a little heavy on the throttle from time to time. I use Chevron 91 octane.

A couple of things to check to help with your mpg. First and foremost, tires! Keep them at the right pressure. Second would be the air filter. I would also try a couple of tanks of 91+ octane gas to clean the system. If you haven't replaced your spark plugs in a while, it might be a good idea to do so (that's a fun job).

I sure some of the experts will chime in on more specific things you can do. I hope this helps.

 

what year max? a 3.0 is noticably more friendly with gas when driving local than a 3.5 from my experience.

i would:
clean/replace air filter (if dirty)
injector cleaner (i used lucas from advance and seemed to boost my mileage)
spark plugs
tire pressure
anything else?

 

It could even go as far as needing to clean the crank and oil. Put some Seafoam/Slick 50 in the oil spot for about 10 miles worth the driving and then drain it and put some discount oil in and flush it(just idle it for a while) and then drain that and put in your regular oil.

Anything listed so far will help IMHO

 

How accurate is the MPG calculator in the Maxima? Because according to mine I get between 27 and 30m MPG, 27 in the city and upwards to 30 on the hwy.

 

From what I have read in other threads, the MPG calculator is about 5mpg off (some). The accurate way of calculating is to reset mileage meter, travel X distance, go to the gas station and fill up your tank, divide the total distance traveled by the total amount of gas you filled up in your car. This is the most accurate way of calculating gas mileages.

Hm I was wondering should I get an induction service just to clean out my throttle. If I do happen to get all these services done, how much will it run me about?

 

I second this. Try putting in some 91 octane. The money you save putting in 87 is insignificant, esp if putting 91 increases your mileage. You could have some bad spark plugs, as well.

 

i had the same kind of mileage on my 02 max with 116K miles on it. worst i've gotten was like 14.5mpg w/ almost all city...best was 22mpg mostly highway. i changed filters changed oil changed this and that and nothing helped.

edit: oh yeah i've always used 91 octane...but the one time i tried 89 just for the heck of it, i got about 1-2 mpg better but car lacked power by then lol

 

This is your rear oxigen sensor, it needs replacement. I had the same problem and it didn't trigger any error codes. After replacement I'm getting around 345 miles on full tank of Canadian 91 gas and local driving. Hwy only gives me above 400 miles. It used to be 260 miles local/290 hwy. After I fixed similar problem with my 93 Max it started to get better mileage than 2k which finally got me thinking .

 

2001 SE with decreasing gas mileage and recently the check engine light came on. Had it checked at Autozone and it shows the O2 sensor is the culprit. Which is what others are saying. I just cannot justify paying over $100 each for a couple of O2 sensors (I know only one is showing bad, but assume the other is in the same condition and should be replaced too.)
I went to the Dollar Store recently and they had the STP Octane Boost, which is great in the Max. It cleans the system and makes 89 octane run like 91 octane gas.
Now I just need to change the O2 sensors :-(

 

I thought the front ones were the important ones..

 

If it says 27 then it REALLY means 23
Not kidding about that.

 

260 all city ha? I'm getting like 210-220 and I think I'm putting about 16 gallons.and that is like 13 something per gallon soo I'm getting worst! I have to do something about this,

When I'm stopped at a light, I get a slight vibration too soo does this mean its time for me to change the plugs too?

 

Me too, I thought it was used for detecting bad catalitic converter only but this is what happened in reality. For what it worth parts guy at the dealership asked me at the end if I was getting crappy mileage and nodded in confirmation that this is the culprit. My mileage improved on 25%, very noticeable.

 

Straight from the FSM:

As usual, clear as mud . May be I should check my front ones as well - may be ECU is always not 'under normal conditions' that's why my mileage improved so much because it didn't have a choice. No error codes though.

 

Hm ... I did have an oxygen sensor replaced couple months ago but I'm not sure which one. The mechanic was my dad's friend and to me he is quite unreliable. After 2 weeks or so the SES light will come back on ... which makes me wonder if he did anything. (Went to him over 10x) So basically there are 4 oxygen sensors, 2 in the front and 2 in the rear. How much will it be to buy all 4 of them? And are they hard to DIY? Just wondering.

 

On my 97 I had all of them go out one after the other.

 

wow that's crazy, does that mean if one fails the others will fail as well?

Edit:: Just came back from Autozone with Chevron 12 oz. Fuel System Cleaner, hope this will work a bit. Also my SES light came on when I was on my way back home, didn't want to go back since I was a block away from home. Hopefully they can tell me which error code occured.

 

Take it easy, it was coincedence, they're not related. Read your code, think, fix the problem. Ask here if in doubt .

 

AMEN my brother.

This is the reason why I came back after being away from this forum for 6 years. I had no major problems with my max {knock on wood for more years} but just recently been having problems with the ignition coils and came here to figure out what to do.

BTW, I recommend that you follow the advice from AndyMan - best damn advice here about correcting your mileage. You know what the second one is, right?


Slow down and don't bunny race from light to light. I do and screws up my mileage.

 

Alright thanks for everyones help. If anything happens I'll let you guys know. Btw which one of you guys is Andy?

Oh and I don't bunny race from light to light, more like turtle race.

 

I just got back from Autozone and they told me I got a P0430 and a P1320 code. Yes the infamous P0430 code ... not REALLY sure what the P1320 code is since it only states "Ignition Signal". I am sure the P0430 is from a defective CAT. Guessing its the bank 2 rear one?

 

my MPGs have been going on a downward spiral too. The car says I get 18.5 with regular fuel. Also occasionally when I start from a warm start the engine Rps drop and it stalls. Usually though it just sputters and comes back to life. I think it's my maf but i'm not sure. I have 110K

 

About a month ago a got those same 2 codes after feeling my engine runing rough. I had them cleared (or reset) at Autozone. The P1320 (ignition) came back but this time along with P0302 (cyliner 2 misfire). I replaced just the cylinder 2 coil and the engine roughness went away. As soon as I get the "moola" I'll replace the rest of them cause in the back of my mind sometimes I hear the engine running not so smooth. BTW, another week went by after that and code P0430 came back to stay. I will be replacing the rear sensor on bank 2.

 

I would check to see if your vehicle has a lazy 02 sensor. Sounds like something is going on with the MAF, or one of your 02 sensors. I had a similar problem with my 01 Max, and the front bank 1 sensor was faulty causing poor gas milage. I would definetely spend $70 to have your vehicle scanned to make sure all your sensors are working properly. The poor gas milage is eating away at your wallet!

 

there are several factor at plays in getting better gas mileage. Is your car properly tuned such as maintence, fuel injector cleaner, air filter changed, oil change, spark plug checked, oxygen sensors??? If not, then look at how many miles on your ODO, and see what you have, then ask yourself, when was the last time you had your plugs changed. I just did mine today, and I only have 58k miles on the ODO, surprisely that my spark is coated with burned on carbon. I'm glad I changed it. Now I have noticeably increase in my gas mileage additionally the power is back up where it was when I got her new.

 

No kidding. Driving to Kentucky and back, one tank showed 31.3 mpg but doing the math gave me 27.4 mpg. All freeway, averaging around 70-75. Average for the entire trip was around 26.5 mpg.

In town, the trip computer shows 22.5-24 mpg and I actually get around 19.5 mpg.

 

Pepboys is doing both Tuneup (sparkplugs change) and Fuel System Cleaner service together for under $200. (including tax) Gonna drop my car off their Sunday when I'm free.

 

yeah i've done similar calculation, same results on my 02. depressing, but still better than my old 98 chevy P/U

Does anybody use a tire pump/air pressure at home? or you guys all hit up gas stations. I've yet to find a good gas station will a reliable Tire gauge

 

There's a tire pump/air pressure machine you can buy from BJ's for only $35. I use it and its pretty accurate. Also the ones at Sunoco gas station's are pretty accurate as well.

 

Stop using ****ty 87.

 

Compared to my V6 626, I get about the same freeway mileage and only about 1 mpg less city. Fair trade for an extra 85 hp, wouldn't you say?

I carry my own tire pressure gauge with me.

 

awww those little 99 cent ones?? hmmm have never got consistance reading from that . maybe need to step up for a $2.99 one

 

LOL!

There really is a difference between the 0.99 and the 2.99 ones, believe it or not.

 

Shift up a gear in town. I was using second (AT) for around town so I could have some engine braking. Mostly running around 3k rpm, changed to using drive w/overdrive on and it has made a big difference. Was getting around 300kms to a tank, now getting 400kms. Approx a 45 mile improvement.

 

Brought it to the shop here's what they did. cleaned MAF, cleaned throttle body, and changed some belt that was on it's way out. I'll report back later to see if this makes the difference. i can already feel that my car feels like it has no hesitation at all, and no more stalling!

 

i lost 5 lbs this month from swimming almost every day, my gas improved by 0.00008 mpg. score

 

Hm are you saying that driving with overdrive on saves more gas? I thought it uses more gas ... guess I'll test this out.

 

I've actually heard a couple people say now that when you turn O/D off in the city, your MPG raises. Lets do some tests!

 

Going down the steet at 65kms in second (approx 40mph) it would run at 3k rpm, it is 1500rpm with the OD kicked in . Lower RPM = better gas milage, in most cases. Of course the OD does not kick in unless your going fast enough, just having it on does not mean it is running in OD. I used to avoid using it as to avoid it hunting for the right gear. If I am driving at a steady pace it is not an issue. I have not checked the mileage with just using Drive only (OD off).