Went to dealership, paid $136 for diagnosis, they didn't find anything wrong with the car. They said its okay for car like this to go 15-16 mpg in a city. They also reset the learning for the car, it was at 92% and now its at 100%, not sure if it will help.

 

ok this will sound odd but it helped me out

put in a new VRT (vapor recovery tank) oddly enuff when my I30 was suckin down more gas then opec that did the trick. got 7MPG back

also check the hoses for cracks and or cuts,

 

^^^^^are you referring to the evap canister? i have close to the same problem as him. But i haven't check my o2 sensors resistance yet

 

yep that would be ithe same thing.

 

Can you tell us a little more about the procedure, how you tested it, cost, etc?

What is it that wears out or otherwise deems replacement on the VRT?

 

From what I understand (5th gen Max shop manual), they can fill up with water over time.

It's also at least possible that in consistently trying to cram every last penny's worth of gas into the tank that you might get liquid gasoline into the evap canister.


Norm

 

I did find a lot of water in mine, as for how much cant say as i took one off my parts car. not very hard to do just a little tight to get at as it is between the fender and spair reccess by the trunk. basicly couple bolts couple hoses just a tight spot to get at. removal of the filler tube did make it a bit easyer to do the job and lets you inspect the lower end of the tube for rust. another problem with this gen car.

 

I went to Orlando Infiniti dealership. The diagnosis was $136. It took them one hour. From what I understand they used expensive (10000$) computer. The scan it, did relearning and stuff like that. They said everything was good, knock sensor is still good. They showed me paper saying that this car runs 17mpg in city so 15-16mpg is right number.

While they were doing the work, I looked at new infinities, they had 19mpg city and like 26mpg highway and below with little font it was saying "Most drivers will get 15-22mpg", so I am wondering, were they right that its normal to get 15-16mpg or not? I am delivering pizzas, so I do a lot of city driving. But before infiniti I used to have little geo prizm with 10 gallon tank and I would be able to drive like 290 miles a tank and I would get like 28mpg in city, now on infiniti I get 230 miles a tank. I understand that geo is only 1.6L, but that seems to be HUGE difference.
Geo 11 Gallons 290 miles/tank
Infiniti 17 Gallons 230 miles/tank

 

Pure physics.

There isn't all that much difference among engines in terms of how much fuel they use per HP demanded (times how long you demand it, given more or less similar driving patterns). Bigger (read heavier) car needs more just to maintain the same pace as the smaller car, never mind the tendency to use more of the power that's available for greater acceleration and/or higher speeds typically reached. Don't forget that having roughly double the displacement means . . . roughly double the fuel usage at idle. How much of that do you get to do?


Norm

 

a full size sedan not best choice for that work, but you can Maximize (pun intended) your MPG the most obvious is be smooth no hard starts or stops roll up to a red light/stop sign don't race to it. keep as much junk out of the car as you can if your not doing much hiway put an extra 8 PSI in the wheels ride will be a bit ruff but you will drop rolling resistance

there is not real magic bullet for better MPG no gee wiss gizmo that will make your 6 sip gas like a 4. just maintain it use high quality plugs wires and O2 sensors (be surprised how much a cheep O2 will hurt MPG) and just drive smart, mashin the gas at the light may be fun but won't get the peparoni extra cheese there that much quicker and will take more out of the tank then it's worth.

 

Okey guys, case is closed. Did 100% highway and got 24.5 MPG
Officially in .gov web site it says 17 city and 24 highway.
Whenever people on this forum were saying that they are getting 18mpg in the traffic, its sounds like bs to me, unless they either drive i30 instead of i35 or they looking at trip computer instead of actually mpg

It turns out that unfortunately this car has pretty bad gas mileage. 16mpg in regular city driving is kinda bad. If you drive in heavy traffic is even worse. So best thing to do is to get brand new m35h

 

16mpg city delivering pizza's is really good. Seriously should have done some research on the car before you bought it
Also do you understand the concept that delivering pizza's in heavy *** sedan with a big engine is not the smartest idea? Def. get a beater and deliver in it.

Not trying to be rude just pointing out the obvious

 

Also LOL at getting a brand new M35h to delivery pizza's in.....thats got to be the stupidest thing Ive ever heard

 

Lol. I wasnt talking about car for pizza delivery but just about gas mileage in general) didnt infiniti said i35 gets 19 mpg?

 

Lol. I wasnt talking about car for pizza delivery but just about gas mileage in general) didnt infiniti said i35 gets 19 mpg in city?

 

Delivering pizza's is by far NOT city driving. Driving very short distances, turning your car off, turning back on, and driving another short distance. How many pizza's are you delivering nightly? A good 20 at least. At domino's we had a few guys who would break 50-100 friday and saturday. And your living in central florida (im guessing orlando). Vacation central. Im gonna say you deliver a good 25-50 orders nightly. So think, you are starting, and moving your car say 50-100 times a night + a very thirsty engine= gas guzzler

 

well, actually I do about 3-12 deliveries on rush schedule. About 10-25 on late driver schedule and about 20-30 on full day. My average delivery is about 3 miles round way. I did counting and it was the same when I had to deliver pizza and drive to college 30 miles everyday and when I just had to deliver pizzas. The results were the same, so I think that delivering pizzas and city driving is nearly identical. As far as I know, Infiniti officially said that this car gets 19 mpg in city and 26 mpg in highway. In city, I never got 19 mpg, even if I drive with no A/C ( when I did that, I got 18). And when I say in city, I was driving about 30% at night, with no traffic at all. Speaking of highway, I drove 100% highway and got 24.5, which is still not close to 26. So I did research before I brought the car and I thought that when I will deliver pizzas, I will get like 80% city and 20% highway, which should of gave me about 20-21mpg. Instead I got 16, so I spent another couple hundred dollars on sensors, spakplugs and other stuff hoping that there was some problem with the mileage. I am not really complaining about a car, I just didn't like that Infiniti gave BS gas mileage. On gov web site (which I later found) it says that i35 gives 17 city and 24 highway.

 

That's because the government website shows adjusted mileage ratings under the new EPA system. It's not that Infiniti gave BS numbers, they were using the old method which was changed in 2008.

 

Well, if they did not bs, how in the world did they come up with 19 mpg In city

 

Read the first two bulleted reasons here.

The test numbers determined for earlier cars - including yours - were generated using a procedure that was not entirely realistic and definitely "optimistic". IOW, you probably could approach 19 if you drove more mildly than you do and could keep the windows closed without having to use the A/C. Might even exceed it.


Norm

 

I see, but don't you think Infiniti still lies about gas mileage on the brand new vehicles?

 

The EPA does the testing and they use their formula. Manufacturers cannot lie about fuel economy ratings. This is independent of whether or not the EPA test reflects real world results.

Edit: Nevermind, apparently the EPA doesn't test all vehicles, only a sample of vehicles each year and takes the automaker's word for the rest of them. The cars are however tested randomly so it probably wouldn't be a good idea for Infiniti to lie. That could become a PR nightmare.

 

Wow really?!? I might have to check that out! My gas is about 17 with 60/40 highway/city. Id love to get some more gas mileage.

 

any suggestions on modifications to bump my 2006 Max to get 30MPG...everything is stock and it reads 23.7 MPG

 

You should get 18/27. If your trip computer stock, reset it.

 

Well, its been a month since I start another job. My gas mileage is still average 15 miles per gallon. On my last fill I counted it to be 12 miles per gallon. Don't know what the heck is going on.

 

You need to make sure you change all of the spark plugs with OEM Spec plugs and change them all at the SAME time. Don't do 3 and then 3 another time. That's a no no. What kind of oil are you using? What kind of gas are you using as well? And I would go ahead, if you haven't already and have the dealer or a trusted shop clean out the throttle body since it looks like there could be some problems doing that yourself (let someone else break it...). Report back with the requested info and we shall go from there.

 

All sparks were changed with OEM plugs, all at the same time. Everything I use is correct. I went to dealership before regarding the issue, they did not find anything in the computer and said that I supposed to get that mileage.

 

What kind of gas? What kind of oil?

 

Usually put 87, sometimes put 93. Oil is syntetic 10-40

 

Oil weight may be a little high. But I guess with higher mileage its ok. Try using 93 for a while. You should see some kind of increase in gas mileage.

 

I just filled my tank up a couple days ago, I had reset the trip odometer at the last re-fuel, and it was around 330 miles. Unfortunately, the gas pump was SOOO SLOW that I ran out of patience and left after only refilling 7 gallons or so, therefore I couldn't calculate fuel mileage... but I regularly get over 300 a tank driving mostly city with some highway mixed in. My car is not stock though.

 

Where to begin? Well first, delivering pizzas in a full sized sedan is not stupid, it's pimp ****. What customer wants to see their driver show up in a beater that looks like **** on the outside and worse on the inside? And what driver wants to spend the bulk of his night driving around in that same piece of ****?

Second, I don't know if you realize this or not but there's a little something called fuel injection that virtually all cars have utilized since the 80's, making starting the engine just as fuel efficient as leaving it at idle for a few seconds.

My guess is that you were stuck inside of that Domino's slapping dough and taking phone orders while the drivers were out listening to music making $80 in tips per night, and you think you know what you're talking about.

Drivers don't care about gas, the company pays for it, the most important thing is rolling around like a ****ing G.

And for the record, I averaged no less than 20 MPG in my 91 while delivering pizza. It's actually worse now that I don't do it anymore, considering each time I drive my car, it needs to warm up first.

 

Now I am probation officer and drive in city. No more pizza delivery, just once in a while on Sundays. Right now I still get exactly same gas mileage as when I was delivering pizzas. I get 15-16 MPG. Not sure what it is. Probably something is still wrong with my car.

 

My I35 has about 56000 miles all stock. I only get around 14 miles local and around 18-19 highway and I drive like a old lady. I think its just the way the car is made. Nothing is wrong with it.

 

Wow, that sounds low to me... but I guess I can't give a good comparison as my car is not stock.

 

I'm willing to take a wild guess and say maybe if we mod our Maxima's way of breathing it may help. I did a SRI on mine and it feels more fuel economic. I may upgrade anything air related on my car (as in intake and exhaust) just to see where it lands me.My goal is 3 to 5 more MPG

 

did you ever figure out your issue??? I'm getting 12 city 16-17 hwy, and did everything you did, even changed PCV fuel filter oil, and cleaned throttle body and MAF, using 93 sunoco, and oil is whatever manual says synthetic castrol.... Please get back to me asap!!!!