Cruise control vs gas consumption

I have been testing for a short period of time, and have been noticing how using my cruise control seems to consume more gas, by as much as 4 miles per gallon.
This all makes sense to me, because it seems that in downhill situations (half the time) it will use the engine compression to ensure I don't pickup speed over the set cruise speed.
I am very surprised however by how much more gas it seems to use.

Have any of you noticed similar findings?

 

How are you testing? I find that overall, cruise provides better MPG as it more closely regulates the amount of fuel needed to maintain speed.

 

I noticed with any kind of incline while in cruise control the down shifting is causing MPG to go down, but when driving long flat stretches it will increase dramatically! Common sense right!

 

This is a common occurrence with any vehicle. As someone who use to be a "hyper miler" when i had my vw tdi i can tell you that if you know what you're doing you can always achieve better milage without cruise control. You get the best milage by being able to regulate throttle position as apposed to speed like a cruise control does, this means slowing down on up hills and gaining speed before going up them and also not using any throttle on down hills. Same can be said for auto for manual, nowdays a lot of manuals epa rating will have lower mpg but thats only with an average driver who doesnt coast in neutral, downshift instead of break, ect. Basically when it comes to milage you can always get better on your own than with a cruise or auto trans.

 

I'm not a hypermiler but, cruise is there to maintain a given speed not to improve MPG. I think for a lot of people it does help MPG but, IMO, it's due to people jerking off the throttle.

However, there may be cruise that does help MPG as well as keeping speed in our future.

https://transportevolved.com/2014/0...e-control-promises-mpg-gains-highway-driving/

 

You really see the benefit of cruise control when driving on mostly flat roads and keeping the speedo under 65mph. Like you said, hills cause a problem because of gear hunting while going uphill and the cruise doesn't let off the gas when going downhill.

 

The problem I've seen with the manual Tacoma's is that when you shift into neutral while coasting, the RPMs don't return to idle (~750 RPMs). Instead, it'll hover around 1200 RPMs.

David

 

Thats wierd, i notice something similar to this with my subaru when first start coasting sometimes it will blip my throttle up on its own. Im wondering if it is an emissions thing to burn off anything in the cat maybe

 

In a Toyota product, it's better for MPG if you coast with the vehicle in gear. While coasting in gear power is cut to the injectors & fuel will be shut off...when placed in neutral the injection is powered and supplying fuel to keep the motor turning.

http://www.caranddriver.com/feature...ng-to-a-stop-do-not-shift-into-neutral-page-3

 

I should have clarified that I was referring to a manual trans, theres no need to coast in an auto since it basically puts you in neutral when you let of the gas unless overdrive is turned off. With a manual trans however you cant coast in gear unless you dont plan to coast very far due to the engine braking. Yes you get better milage coasting in gear with a stick also but unless you're going down hill or coming to a stop its not practical.

 

I owned a TDi for a while...lived the MPG and always got higher than the EPA rating (mid to high 50s sometimes) but, I HATED the car...

What's your best?

 

I had an 06 TDI i loved it unless it snowed out which was why i ended up getting rid of it but my best was 51mpg on a tank but i averaged 45 even driving it like i stole it.

 

I had the same problem in my 2007 Ram 1500, better gas mileage not having cruise control than using it. Cruise control does not control load. Cruise control dosent know to let off the throttle when going down hill nor anticipate a hill and either slow down a little going up hill or to use your momentum to help a little. If you could rather set your load on the engine we would all find our MPG to be as advertised.

 

If there are any hills at all my cruise will do the same. By "hills" I mean anything so much as an overpass and its wanting 4th gear. Heaven forbid there are actual mountains.
I go 48miles round trip for work and 90% interstate. Avg over a workweek, in cruise, ~19mpg. Without cruise ~24mpg.

 

Interesting stuff. I drive with cruise on most of the time, even at 35mph Screw the mileage

 

As with others, I do better without the cruise since I will naturally tolerate ups/downs of 2 or 3 mph while holding the throttle at a constant position. Cruise will downshift and burn fuel to maintain the exact set speed up hills. It seems to work okay if I set the cruise about 3 or 4 mph below where I intend to drive and let it be a "backstop" in case I lose focus and start slowing too much doing things myself.

 

I like using cruise control in my Frontier. Holds 6th through hills at 1750rpm. Mountain passes in 5th at 2000rpm. Accelerates without needing to downshift. All this makes it quite good on fuel, pretty consistent 22.5mpg on the highway. All hail the manual gearbox.

 

I think you're lost. This is the Tacoma forum.

 

Thank you all. Many of you confirmed what I thought and put it in better words than me.
Someone asked me how I did my test. Doing the same commute, I'd alternate with on my way up and workout on my way back.
I am now convinced that cruise control does use more gas.
Thanks for the replies

 

OP yeah I have been having the same issues as well. For no apparent reason it will kick it up to 3500rpms on straight and level interstate and just stay there for as long as I allow it to. Also really disappointed with my mileage overall on average I'm getting between 14-17 per gallon combined. I nurse the throttle, don't have ECT on, factory wheels and tires, not in 4wd or anything. Toyota says it's all within spec, it's fine I'll call every time I get some free time. Besides that I love my turd gen!