Highway gas mileage sucks.

It seems that when I'm driving on the highway around 65 to 75 mph my truck has a hard time wanting to shift into 6th gear and it's even worse if cruise control is on. I get less than 18 on the highway most of the time because of this. And yes I've had the transmission update. Anyone else? Any suggestions?

 

I found using my cruise control dropped my mileage by 1-2mpg, and that's on flat highways in Florida at 70-75mph.

I'd also expect you are losing some mileage due to winter blend gas which should change in the next few months.

I use ethanol free fuel only (more BTU/gallon) and fill my tires to 35psi and get 21-23mpg with my taco.

 

Shift Sense Pro

 

Only go downhill and it will improve some.

 

Yeah...I get like 17 on the freeway.

 

Also, a higher profile vehicle will be more affected by wind resistance. The sweet spot for the tacoma seems to be in the 50 mph range give or take some.

 

what modifications (if any) do you have? i.e. lift? bigger tires?

 

For me, with 265/75 tires, I've found the best mileage I get is between 45-65mph. Its actually more fuel efficient for me to take side roads than the highway out here.

 

100% stock, DCSB 4WD. If I am 65-70MPH, I get an honest 23mpg. This is all highway, say ideal conditions (no wind, etc), no major mountain passes. And I'm running it on 85 octane. Mine goes into 6th without issues. Have you had your trans fluid checked? And as mentioned above, any mods, especially tires?

 

Noticed the same using cruise at 72, slight hill it wants to downshift.

 

I am getting average of 20.5 to 21 mpg on highway (few small hills here and there). Manual tranny. 2000 rpms at 60mph.

 

My gas mileage varies, how can you really tell if you're in 6th gear? I've had the trans update but, didn't notice a difference.

 

Ever since I added my RTT, I get about 17mpg average on freeway- been using it a lot lately so its staying up probably intil the end of summer now.

 

You have all kinds of problems. You are driving at altitude, you are driving at a speed over the "best speed most efficient speed" of 55 mph and you are driving at a time when winter blend fuel is still being used. These three things equate to 3-4 mpg. Any mods you have will reduce it even more.

If you drove the exact same route in the summer a few thousand feet lower at speeds 10 mph slower you would get 21-22 mpg.

 

Anything over 70 and my mileage drops like a stone. 55- 65mph I purr along at about 1800 rpms for about 22-23 mpg on the interstate at sea level.

CC does not conserve fuel, it tells the engine and transmission to do what it can to maintain speed regardless of wind or incline.

 

I’ve noticed I get a little better mileage on a higher octaine: say 89+
But there have been times where I get around 18.
I too wish there were a way to get better mileage. The best I’ve gotten is 22.
Also I don’t know what the tranny update is? Nor do I know if I have it? My truck is a 17

 

19.5mpg highway this weekend. average speed 70mph with 800 lbs of people/gear. Hilly driving, temperatures mostly above freezing.

 

I think what we’re all talking about here is normal.

Every automatic vehicle that I’ve owned in the last 40 years downshifts at high speed when encountering a hill. Even the powerful turbo ones when traveling at higher speeds. And most of them didn’t get high mpg at high speed, although a few did better than I expected while sometimes traveling in the 60 to 65 mph range, and then that was mostly calculated on flat highway.

Yes, I know, the torquey 2nd gen 4.0 never downshifts on hills!

EPA estimates are established using speeds far below 70 or 75 mph. At that speed pushing against the air, most cars and a lot of trucks with higher coefficients of drag such as our Tacomas will not get close to their EPA mileage rating.

And we need to hand calculate that, not rely on the dash computer. Yes I know, the vehicle computers are sometimes pretty accurate.

Cars with low aerodynamic drag with high horsepower, high torque and manual transmissions or auto transmissions with lots of gears have a good or better chance of attaining higher fuel mileage at higher speeds.

And, of course there are slight differences between testing on a dynamometer and real world testing on the road.

Not every vehicle from every manufacturer is real world tested on city and highway cycles by the EPA.

The manufacturers are left to test on their own to arrive at that number on the window sticker for many of their vehicles.

I think the important factors to consider are: weight, drag, gearing, horsepower and torque and how they relate to RPM and speed.

As they used to often say, your mileage may vary.

 

Yup, 70 mph seems to be the break-over point for me too.

 

I picked up and threw the front spoiler on my Off Road. So far I can't say positively but it seemed to help a small amount when cruising along at about 50mph.

Also tires make a big difference. I got 18mpg with the stock tires and not driving like grandma. Now with only 1 inch bigger tires but MT E load range I get 14.5 driving the same way or 17ish if I baby it.