'01 QX4 - MPG Improvements? Mods?

[Inglewood2]

New to the forum...hoping that someone here can help me out! I recently purchased my 2nd Infiniti QX4 - in the last 3 years. I sold the first one that I owed incredibly too much on and downgraded to a Jeep Grand Cherokee Limited, which I sold again and bought my '01 QX4 4X4 with navigation...love the Q! My only gripe is that the mileage is just terrible...even in 2wd mode, my JGC (with full time AWD) got about 75 more miles to a tank (or more!). The tank sizes are almost identical, and both are a V6 with approximately the same amount of horsepower.

I just replaced the driver's side O2 sensor in the rear, as that was the code that the diagnostics at Autozone kicked out. My mileage for a tank went from about 260 to 300, so I guess that I am getting about what I should be getting for a tank...approx 17 mpg. The Q supposedly gets 15/19 for mileage, but is there any way that I could improve this? Funny thing is that Ive gotten as good of mileage with 87 octane as with 91 or 93...so gas grade seems to be a moot point just as I thought.

Is there anything else I should be replacing (filters, other O2 sensors, spark plugs) that might help at all? Everything seems to be fine, and not in need of replacement. The car is mint, and only has 45k on it...very low for an '01. Furthermore, are there any mods that anyone knows of which would help me get some extra miles out of a tank? These $50 fillups on a weekly basis are bustin my balls!!

Any help is much appreciated!!

[driverdriver]

Its a SUV, that is known to be thirsty, if I'm not mistaked its got a 3.5 VQ series under the hood. The high center of gravity puts it at a aerodynamic disadvantage, creating more drag. The higher you are and the faster you go, the more fuel you will use. Try using cruise control and sticking to the speed limit. I know its made a slight difference with my Cherokee(although when gas goes really high-I drive one of the sedans-cheaper running costs). Also check out the sulphur levels in your gas. Not all gasoline sold is the same. Higher sulphur levels lead to lower fuel economy. Most environmental groups have done studies on clean gas (clean meaning low sulphur). Try using a clean gasoline.

If that doesn't work and your still pissed of at paying for gasoline I would suggest trading it in more a fuel efficient sedan.

[Inglewood2]

I am aware that the QX4 is thirsty, and I should have known what I was getting into...

As it is, I am using the cruise and accelerating/braking as gently as humanly possible, still with moderate results. I know its no sedan, but I just wanted to see if anyone has had any luck with increasing mileage using mods or replacing certain components. Otherwise, there will probably be a mint QX4 with navigation for sale sometime soon on this site...

Any help is much appreciated.

Thanks!