I just bought a 04 for my wife and I will use it to tow my racecar some.
Anyways gas mileage is lower than I expected around 13 mpg is that normal?
Is 93 octane really needed? If so has anyone retune the ECU to run regular.
What is the compression ration of the motor?
And last but not least is the motor timing belt or chain. Thanks Chad

 

Is this a Montero or a Montero Sport. These are two entirely different vehicles Chad, so can't comment on the mpg just yet.

93 octane is not necessary at all on either the 6G75 (3.8L) or the 6G74 (3.5L). I run 91 octane as recommended. That being said, I also ran it on 87 octane for about 4 months when I first got it (to see if 91 was necessary) and it ran perfectly well but a little less pep. Also use it to tow trailer now, so choose to use 91.

Compression is 10:1 on both engines.

Engines use a Timing Belt, but also happen to be Interference Engines, so I would not put off the Timing Belt Service.

Cheers

 

Mine is a montero not sport. Thanks Chad

 

On my '03 Limited, 13 mpg is about right around town. On the highway, at a stable 65-70 mph, you will do much better (I have seen 20). I use 89 octane midgrade, as a previous poster stated, it runs fine on 87, but loses some pep. I noticed no real difference between 89 and 91, so went with the midgrade. This is at sea level, so your experience may vary.