2015 getting awful mpg...help!

Some crazy low MPG numbers reported in the thread. In Florida I consistently averaged around 22 MPG with the stock setup from the start. That is with a 4.0 DCSB Sport. I picked the truck up with 4 miles on it. With the mods done my last fill up was 18 MPG. I track every fill since I drive many miles. I fill up when the light goes on which is about 18 gallons consumed. I fill until the nozzle kicks and NO MORE. If you fill more than that you are asking for trouble.

I only run 87 octane. All fuel I use has ethanol. With the winter fuel I lose 1 MPG. I will get around 19 MPG once the summer fuel hits. My tires are filled to 34-35.

 

At today's prices topping off to next dollar could be 1/2 gallon + or almost none.

 

I don't know if it's already been mentioned, but I would think the cold air itself contributes to more fuel consumption as well. Anyone who has ridden a motorcycle in cold weather will notice how much denser the air is. You can definitely feel it. A vehicle does not move through the air as easily as when it's warm out. However minor, I'm sure the motor has more of a load on it to maintain the same speeds in colder weather.

 

The above statement is not necessarily true. The 4.0 was designed to make the most power with 91 octane, but can detune itself to run 87. People who run 91 or better say they see a slight increase in mpg, enough to offset the slight increase in cost.

 

I've run 91 in every tank since new. I have an 11 year old truck with 80,000 miles, with Toyo AT's, and a 2" lift, and average 19-20 in the warmer months. I've heard the cheaper grade also contributes to the "Taco Tick", which I have never had.

 

I got that number from my ultra gauge

 

I get 15mpg city and there isnt anything wrong with my truck.

 

Sconnie here too and I haven't checked over the past tank or two but I was getting 14.6 as well. Shitty.

 

what problems would come up from filling over one click?

 

Not one I have experienced on my three Tacomas... but if you fill up to the point gas spills out then there is some kind of sensor issue I read once? I have never filled up to overflow, but in Mexico on a couple of occasions the attendant has... but nothing bad other than some gas on my paint.

 

It can mess with your venting system in the tank

 

Btw, I would love a 4.0. My old 2.7 got 14.5 mpg last time I filled up

 

I ran premium and saw no improvement in MPGs nor did I feel any. Around here premium sells @ about a 20% premium to regular so I would have to get 24 mpg to break even.

 

14 MPG here but I have a tendency to step it down at times 12-13MPG. I was getting 17-19 before the supercharger.

 

Um no. Zero chance mpg increases enough to offset the cost of premium. When they say slight , they mean maybe 2-5%.

 

You guys claiming high MPG numbers need to include if your truck is 4x2 or 4x4.

My '15 averages around 17 combined. Haven't gone on any long highway trips to know the highway mpg.

 

Am I correct to assume if they are TRD Sport/Off Road that they are all 4WD? Other than that it is anyone's guess!

 

I think TRD Sport can be 4x2. TRD OR can only be 4x4.

 

Nope. You can order both packages in 2wd or 4wd

 

Did you run 1 tank of 91, or did you run several tanks? The computer software Toyota uses takes quite a while to completely adjust to the difference in octane.

All you have to do is do the research. Plenty of threads here on it where people have switched to 91 from 87, and they got 1-2 better mpg and the few extra cents per gallon paid for itself.