I'm going on a trip this weekend and I wanted to optimize my gas mileage to see what my car can really get.
So the question is would I get better or worse gas mileage (72mph on highway) using cruise control or driving moderately?
It's something like a 250 mile trip.

 

well if your cruising along at 72mph your gonna be turning the same rpms n what not either way you go , if your on it hard at 72mph chances are your not gonna be at 72 for very long so its more of an option for whats easiest for you then saving gas

 

my dad tried convincing me that cruise uses more gas which got me all confused
figured i'd ask ppl that have experience...lol

 

haha yea i dont see how it would use more gas i mean sure it would keep it at a certain speed/rpm the whole time but thats the same as if your just cruising down the road ya kno, 60mph is 60mph, 65 is 65 2800rpms is 2800rpms.so on and so forth ya know. only thing that would really hurt you is if its stop and go constantly but highway driving will be fine which ever way you decide to go

 

Cruise will give you the best mileage, your speed does not fluctuate, also, you are not concentrating on your speedo all the time, so the journey is more relaxing. I got very good returns on a recent run to Scotland.

 

Use Cruise for best gas mileage UNLESS it's a hilly road. In this scenario, the cruise may downshift going uphill (when the speed suddenly drops below the setting) in an all out effort to maintain the set speed.

Of course, you'll get better MPG if you set the cruise at 65 instead of 72. Or even better if you set it at 60. and so on...

 

I think the reason cruise control is more efficient is the fact that it can keep the speed constant while your foot on the gas will likely allow fluctuations. There likely will be times when you go faster than the chosen speed and then the fuel efficiency goes down (higher speed burns more gas). And when you drop below the chosen speed, although you'll be more efficient, when you accelerate to get back to the chosen speed you may burn more gas to attain that speed such that the gas burnt during acceleration exceeds the savings from the lower speed. And if that happens then the car which would have had a steady speed would also have been more fuel efficient.

 

yea the cruise thing just wasnt doin it for me because i got tired of being passed by everyone...

so i averaged a little over 26 mpg on a 400 mile trip at 70-80mph