Anyone have any good tips?

I'm down to 17mpg with mostly hwy. It's been getting progressivly worse over the last 5 months. Bad gas? Doubt it as I'm filling up here there and everywhere, literally.

I've got the tires to 28 front/ 35 rear and I'm thinking of going up to 30 in the front (tires have a max of 35). 225/70-16's no lift. Air filter looks OK but I'm gonna replace it anyways as part of a yearly schedule I have.

Tune up was done last summer and that did help. I'm used to getting 20-22 average. 25 on mostly hwy trips, and now it's 19mpg on mostly hwy. No excess weight in the car, in fact I lost 25lbs from last summer.

Would going to a 17" or 18" wheel/tire combo help? I've seen where the lower profile causes less rolling resistance. 2mpg saves me $300 a year with the amount driving I do (80 miles per day MINIMUM - 550 miles on Tuesday and Wed - Total 1100). And it's an excuse to get new ones w/tires... Right...

You are accounting for the difference in tire height, correct?  The tires you have now are a bit taller than the stockers so your odo will be reading slightly lower than you have actually travelled.

How much of a tune up?  Spark plugs only?  Trans fluid, axle lube, t-case, FUEL FILTER, air filter, etc?
How many miles?  Cat and o2 sensors ever been checked or changed?

Check engine light on?

Using AC more?




Dunno if I beleive the idea that bigger wheels give you less rolling resistance.  At a minimum they weigh more so you've got higher unsprung weight.

Yea, that's accounting in 5% difference in tire height.

A/C - Always running it. Except not as much in the winter, but it's Climate Control so it turns itself on in the Auto mode.

I actually had to get NEW tires yesterday due to some major tire issues in the front. Even larger so I'm expecting a slight drop, again I'll add in the percentage to the ODO reading on fill up. It's riding much smoother and easier now so maybe it was chewed up front tires. 225/75-16 AT's are under it now. OD=30.1".

Tune up was plugs only. Timing is controlled by the computer, direct ignition system. All fluids are Synthetic, and are fresh. Air filter will be replaced this week, K&N now makes one for the 04+ models so I think I'm going that way.

O2 Sensors are original but were checked out-OK. Mechanic is a friends and I had him look at it 3 weeks ago. Neither of us could find anything out of spec. We changed fluids and even then it made no difference.

I'll be filling up again tomorrow, after that I'll check MPG again next week and report back. It may be as simple as the front tires and slight alignment issue. BTW: ROTATE YOUR TIRES EVERY 5K MILES!!!!

Well on the new tires now for 3/4 tank and it's back up to 21mpg... I can't beleive it was the balancing causing it... Alignment was out .09" but that's not enough I don't think.

Either way it seems as though it was the front tires... Can balancing really cause that much of a difference? I did notice when I let off the gas it coasts alot more than it did before, Odd considering the new tires are actually larger. Braking isn't as good as before, gotta apply more pressure on the stop pedal, that's to be expected.

An alignment can definitely cut into your mpg.  Think about it, .09" isn't much but it is a noticeable angle and that's the tires pointing AWAY from each other and trying to make the vehicle go in two different directions at the same time.
Meanwhile you get more rolling resistance from oddly worn tires...

It snowballs.