15 MPG?? What's the Problem?
 

I have a 2k2 GLE Max with 28K miles,

I currently get an average of 15mpg. Thats because I fill up 14 gallons and get 210 miles before I have to fill up another 14 gallons what's going on? Car getting ****tier? I have a custom exhaust system (2.25 id) stock muffler.

Do I need a tune up ?

Re: 15 MPG?? What's the Problem?
 

I think you need the "Lead Foot TSB". :) Ever since I lightened the load on my accelerator, I've gotten much better gas mileage. Are you doing a lot of stop-n-go? Back when my 02 was new, I used to get 18-20, but it increased after I got over its power and broke in the engine... but at 28K you should be fine.

Re: Re: 15 MPG?? What's the Problem?
 

I drive under 3k rpms, but I do make ALOT of short trips that might be the problem also. I do get about 385 miles on the highway.

Lots of factors ...
 

1. Most important ... LEAD FOOTITIS ... cure it to increase mpg.
2. Winter blend gasoline ... at least 10% loss in mileage in most locales.
3. Check tire inflation ... I run mine at around 32-34.
4. Stop and Go driving, kills mileage.
5. Make sure your oil is 5-30, preferably synthetic.
6. Mods rarely help mileage, live with knowing your changes probably lost 1- 3 mpg, depending on what else you've done.
7. Make sure your air cleaner is clean, if not replace.


My first tank I got 15mpg on a brand new 03 SE. I was just driving it a little hard. Not beating it, but exercising it, as it's brand new. Now that it's more broken in at about 1500 miles, I just got 27 1/2 on the highway (calculated, not the mpg guage). Now around town I get 21-22. I'm surprised there's so much variance between around town and highway too. I have an Acura Legend that gets 22.5mpg no matter how you drive it, no matter what season, with or without A/C. The Nissan varies wildly from 15-16 to 26-30 depending on driving styles and conditions.

thats how newer cars are. they can get low mileage in city driving but much better on the highway. i guess that they are simply more efficent on highways. as for lead footitis curing it is not always easy

after i put my Injen CAI in i lost ALOT of MPG.

Before i could get 310ish miles untill i needed to fill-up

Now i can hardly get 270-280!

As for lead footitis, i have that, im trying to cure it, but yes, i do alot of stop and go; Had brakes replaced already.

As for the oil, I use 10w30, is it better for me to use 5w30?? I live in southern florida which gets about 87-93 degrees out this time of year. I've also heard some people saying the more weight oil slows the car's accel down? and that my buddy runs 5w30 in his acura and its faster than when he ran 10w40 before he has over 114k miles.

you may not believe me but it's not the injen, it's your driving. I just installed one and went through the same thing. I liked hearing it so I'd "get on it" a little more off lights and stop signs. I made a conscious effort not to go over 3k rpm and got the same mileage I got before I installed the injen.

You have alead foot or do alot of city driving. I average about 360 miles to a tank with an Injen intake and do about 50/50 city/hwy driving...

Re: Re: Re: 15 MPG?? What's the Problem?
 

My drive to work definitely ruins the MPG... 2 miles each way is a benefit time-wise, but sucks MPG-wise. I actually got the DTE and Odometer to read 470+ this weekend going home. I think if I continued driving up further north, I'd definitely have hit my 500 mile goal!!!

Re: Re: Re: Re: 15 MPG?? What's the Problem?
 

What was you average mph? I know if I cruise @ 80 all the time when I goto work on the highway I can barely get like 250. But if I stick it to 60mph all the way I can increse it to 310+.

Re: Re: Re: Re: 15 MPG?? What's the Problem?
 

HOT DAMN! 500 MILE GOAL!?!

I get about 230 miles on the odo until the light comes on!

Now at 55mph cruise control, i get about 390-410

****...i thought 270 was good...
thats what i get

It's your Air/Fuel mixture. The 2.25" piping is messing it up. I had the same problem when I installed my Y/B/Cat. I ended up installing a Greddy E-Manage unit to adjust the signal from the MAF going to the computer.

Under normal stop-and-go conditions, I got:
Before Y/B/Cat - 19-20 MPG
After Y/B/Cat, but before Greddy - 16-17 MPG
After Y/B/Cat/Greddy - 19-20 MPG

Under cruising conditions, I got:
Before Y/B/Cat - 22-23 MPG
After Y/B/Cat, but before Greddy - 19-21 MPG
After Y/B/Cat/Greddy - 24-27 MPG

So you can see, I get better gas milage with the unit installed. Basically, it's correcting the problems that were created by the exhaust piping, and reverting the ECU back to what it was when the car was stock (maybe even a tab bit better).

I got 440 miles on a tank without seeing the fuel-is-empty light go on, and the unit hasn't been fully tuned. I've only adjusted 5 settings on it (2k, 3k, 4k, 5k, and 6k) and I've got 11 more to go.

So the ECU is basically compensating for the extra exhaust gases with larger dia? How much was the unit? This will certainly void my warranty huh? Dealer says its the exhaust piping also. I hope they do my ECU upgrade TSB for me.

when you hit 7k rpms, you need to shift!!

driving around in 1st gear all the time isn't going to yield high miles per gallon :D :D :p

Neither is driving in 6th!:laugh:

The unit runs about $350. The basic unit will get the job done, however if you want to customize your results, you'll need a Windows-based PC and their E-Manage software. The software package is an extra $130-150 and comes with a 9 pin serial connection on it.

The ECU is reading the extra exhaust air and is sending extra fuel to compensate for the air input, however, the air input didn't change. This results in your running really rich, especially at higher RPMs.

I was running the air/fuel in the 11s at WOT. Now I've gotten the unit to be between 13.7 and 14.1 (depending on RPMs). I've yet to spend the time testing the unit to see if I can lean the car out a little more and get more HP.

hmmm, I need to install a CAI

I've got a PR CAI and the results were still rich. I'd say go pay the money to dyno your car and make sure they will give you your air/fuel mixture. Once you have the dyno results, look to see if the air/fuel stays consistently around 13.5 to 14.5. If not, you'll need an engine management unit like the Greddy E-Manage or the APEXi SAFC (or SAFC II).

It's not his mods folks. And it's not entirely his driving either. Nissans get crap gas mileage, we all know this.

Before you procede further you should take your car to the dyno and make a few runs with the widebad O2 plugged up to it. The take a good look at your A/F chart or post it on here for us to see. Some 2002's run extremely rich becasue of bad sensor readings going to the ECU. Scott's car is running 11 to 1 NA which is WAY too much fuel.

Re: Re: Re: Re: Re: 15 MPG?? What's the Problem?
 

Remember I'm calculating total miles (potentially) meaning adding up the amount I've travelled and the amount the DTE meter reads. I'm doing an average cruise speed of 70-75 on the highway and I try not to accelerate hard unless I really need to pick up speed quickly.

NISSANS get crap mileage????

Is this fact?;)

Wow, I guess I gotta try that. I noticed my miles per tank (mpt) went from 340-350 to now 275-285. I have actually been pushing the pedal a lil.