Another MPG... IM STUMPED

[iowajosh]

The only way to figure mpg is miles/gallons. Correct for tire size.
We don't know where the OP is from. Maybe he has really heavy tires, also.


I've been checking the 4cy 2runner for mpg at every fill. In the winter it was disappointing. I think it was 16 with sandbags in the rear and some warmup time. My drive is 5 miles turn, repeat 3x. I just am not going to get highway mpg. But it shouldn't be close to city mpg, either. On e-10. I put a tank of e-0 in and didn't see a difference. I just put a factory style exhaust back in, maybe that will help. There was a small leak down by the O2's. I just broke 20mpg in my last tank. Warmer weather and driving like a grandpa. Auto trans. p247/78/16

Isn't the rule of thumb -1 mpg for every 200#?
I've read roof racks are -1 mpg.
Heavy tires probably count for 2x dead weight unless you're on the highway, cruising.
A lift seems to be -mpg.
e-10 is -1 mpg
Hilly areas and fast traffic are - mpg.

I guess I don't have any answers, just thinking out loud here. I've been thinking all the same things. Trying to find "the answer." I was hoping the 4cyl would at least get some decent mpg and it may, I just need a road trip to check it.

 

[fish0281]

Has anyone tried one of thos motovac services?

Sounds to me like small exhaust leaks (upstream of the O2's) can be a culprit too - what's the best way to test for that?

 

[redbull9944]

I agree with checking the o2 sensors. My mileage on my STOCK '01 was absolutely terrible before the sensor swap. I was getting around 210 miles/tank. Now that I changed the o2 sensors, I'm getting 270 per tank.

 

[1985taylor1925]

I used to average around 20 highway, 16-17 city, which is pretty good. When I got new tires in January it went way down. Im now averaging around 16.5 with 75% highway driving. I went with 265 75s, so slightly bigger. But I think its the weight thats killing me. Theyre a 6 ply rather than 4 ply.

A few other thoughts . . . how many of you guys have done the rear diff breather mod? Some have claimed that it really freed up their rear axel, which would help mpg. Bad u joints could also hurt mpg. If they are worn enough theyll cause a vibration. And that vibration sucks a little bit of power from the engine.

 

[98OzarksRunner]

A few other thoughts . . . how many of you guys have done the rear diff breather mod? Some have claimed that it really freed up their rear axel, which would help mpg.

The diff mod won't make any difference. Air, even pressurized air (and there won't be any more or less with the mod) isn't going to affect how the diff spins. Now if you had EXTREMELY accurate instruments and compared the amount of power to turn the diff at sea level vs an absolute vacuum (in outer space) you might notice a slight difference - like .0000001% more power required to turn it at sea level.