2006 Sport V6 Gas Mileage Drop

[claydoctor]

Just in the last few months I have seen a 1-2 mpg drop in gas mileage. It's supposed to get 17-22 and I was averaging about 20 actually calculating it.
Possible factors.
1. Got new tires. Michelins LTX/MS2
2. Much of my mileage is highway and speed limit just went from 65-70.
3. Have gone way over 30K w/o changing plugs. Total mileage-134,000
It runs fine but I'm suddenly filling it up more often and with climbing gas prices. I carefully and gently cleaned the MAS sensor. Not sure that didn't make it worse.
Any other ideas? Thanks.

 

[Doozi]

Are you in a cold climate? If so, it's probably winter gas coupled with colder temperatures.

Nice choice in 4Runners, by the way!

~Doozi

 

[DaveS]

Yep - winter gas will hit you hard on mpg - at least what you are seeing. Falling tire pressures in cold temperatures and gas burnt on cold starts will only add to it. Unless you are somewhere far enough south to escape all this you are doing well!

 

[KB084RUNNER]

Do the plugs, clean ther MAF sensor, ditch the HCF and keep your tires at 34psi.

 

[claydoctor]

Do the plugs, clean ther MAF sensor, ditch the HCF and keep your tires at 34psi.

I'm sorry, what's an "HCF". My tires are at 35 psi and if it's the gas, I don't remember this problem last winter. Appreciate all the ideas, however.

 

[Nuke]

HCF = Hydrocarbon Filter. It's between your stock paper filter and the throttle body. Some consider removing it to provide a bit more power. It requires drilling out some plastic rivets.

Winter fuel and winter driving in general will reduce fuel mileage. Plus, I've ALWAYS had a fuel mileage drop after putting new rubber on the car. Other than running a can of SeaFoam or a good fule system cleaner thru a tank or 2, I'd give it time. Also, with those new tires, be sure the shop inflated them to about 32 PSI.

 

[rwilliams]

Are you in a cold climate? If so, it's probably winter gas coupled with colder temperatures.

Nice choice in 4Runners, by the way!

~Doozi

100% true about the winter gas blend myth. There is your reason. And it's not just in cold climate areas.

 

[claydoctor]

HCF = Hydrocarbon Filter. It's between your stock paper filter and the throttle body. Some consider removing it to provide a bit more power. It requires drilling out some plastic rivets.

Winter fuel and winter driving in general will reduce fuel mileage. Plus, I've ALWAYS had a fuel mileage drop after putting new rubber on the car. Other than running a can of SeaFoam or a good fule system cleaner thru a tank or 2, I'd give it time. Also, with those new tires, be sure the shop inflated them to about 32 PSI.

It's a permanent filter? What's it made of?

 

[12guns]

It's a thin filter made out of some kind of media w/ carbon. It traps unburned fumes from seeping out of the airbox. Pretty much does a whole lot of nothing. Any btw, all you need is a screwdriver to pry is out, the rivits will pop right off. No drilling needed. Takes 30 seconds to remove. You'll hear an ever so slightly increase in throttle noise, though probably not noticable.
I went the extra step and did a kind of redneck airbox mod...sounds awesome and gets better airflow. I'll try to post up today.