2015 getting awful mpg...help!

That's great... lucky you! Maybe your gas is not laced with ethanol? I turn 59 in 7 mos. but wish I got at least 18 mpg normally! Have fun and we are never too old!

 

Good info, do you know at what point the engine would start sputtering? Miles after light on maybe?

 

Never ever allow the truck to run out! Just bad stuff... I have at the lowest once put almost 20 gallons in... But typically fill up at 1/4 tank or when the light comes on.
When I fill up, I zero the trip odometer and I can see mile mileage based on where the gauge needle is at various miles traveled. If I get 90 miles when it is at the 3/4 line (rare), then that is 18 mpg. Usually, it is 80 miles on the odometer at the 3/4 line (16 mpg) or 75 miles (15 mpg).

 

Then the dealer didn't fill it up and you did not do a accurate calculation if your above the 1/2 line at 164 then you are getting a lot better then 15 mpg.. People start threads like this all the time with the same result. But you could calculate it pretty accurately if you check it today at half a tank..

 

At the half full line on the gauge: 9 gallons burned from a filled gas tank, going 164 miles = 18.2 MPG

 

Only thing 89 will do is cost you more

 

10% ethanol not just Ca.. It is anywhere the clean air standards call for it, like DFW. I push 21 during warmer weather on a regular basis. I use to go over 20 on occasions until they raised our hwy speed limits. If I ran 65 on hwy I know I would hit 21. My daily drive is most all interstate with 3 stops signs and one light.

 

There's one other variable not mentioned in this thread yet that is relevant to cold climates... The defrost and defrost/floor mix settings for your temp control automatically kick in the AC compressor even though the AC light is not lit. In tandem with the other seasonal explanations this can contribute to a decline in MPG during winter if you use either of those two temp settings regularly.

 

Is that true even if the fan is set to off?

 

My AC light comes on but, I can push AC the button and it kills it. The purpose is to de-humidify the air for quicker de-fogging.

 

The AC cycles when either defrost setting is selected

 

Does this apply to all models? Strange I can always feel when I switch on my AC but never felt it switch on with the defroster on..

 

The only way to get better fuel economy is adding one of these.

 

I don't think so. Setting the fan to off should keep the compressor from kicking in but I'm not 100% sure.

The AC light must come on in older models, it doesn't in my '15. But you're correct, quicker defogging is the point.

See my point above, may be different for your '07. But the auto AC on defrost settings is the norm for my '15.

 

Yes with fan off your a/c is not on, whether set on defrost or any other setting.

 

It isn't always necessary to "de-humidify" air while running the defrost. De-fogging is a more common requirement with above freezing humid climate. When it is 32F or below and the air is already dry, the a/c doesn't de-humidify since it requires cooling air below it's current temperature to condense that humidity. Works great with hot humid summer air, but not for cold air, which is why it would be nice to turn it off when you don't need it.

You can get enough air flow to the windshield using the floor position and not have the a/c running at the same time.

 

Glad to see this. I've averaged around 15.8 mpg since the day I got her, and that's with 6" lift and 35" MTs. I was beginning to think I've somehow been calculating mpg's wrong all this time when I see folks driving stock setups and getting the same or worse mileage.

 

I was told the AC comes on in defrost mode to exercise the compressor. Here in the northeast I would not run the AC for months if not for this. I just wish there was a way to turn the AC off in defrost. Or at least the light should come on. Running the fan at the floor setting still provides a good amount of air to the windshield.

 

I do the same! I wonder why our readings are so different, but we get nearly the same MPG? When I fill up, I usually fill up until the first click then add fuel until I round up to the nearest dollar.

I can drive for 60 miles before the needle begins to drop from above the 'F' to the actual fuel gauge.

I can drive for 120 miles before the needle indicates 3/4 of a tank.

I can drive for 200 miles before the needle indicates 1/2 of a tank.

BUT my MPG's average 18.1 MPG with a personal best of 18.9. Based upon the figures you posted earlier I should be getting around 22MPG's.

Not saying you're wrong whatsoever, just odd that they're so different.

http://www.fuelly.com/car/toyota/tacoma/2015/ik0nik/391034/fuelchart For reference!

 

Interesting, my needle drops to the F line when 2 gallons are consumed, or 30-32 miles town driving. As I said, when it reaches the 3/4 line that is 5 gallons consumed, or 75-80 miles town driving (15-16 mpg).

The next "1/4" tank drop from 3/4 to 1/2 lines is = to 4 more gallons, or 9 total consumed from fill up. That's 135-144 miles on the odometer at 15-16 mpg.

These amounts have been consistant the 6 years I have driven this Tacoma. The only way to add more miles if I filled it to the opening rather than stop at the normal click off + rounding up a little. The variation we all may have depends on how much we add after the pump first clicks off. That's why I add (+/- 0.5 gal) to my chart.