From the time your vehicle is stopped, how long does the "auto start-stop" engage for? Does it really save gas by doing turning off then on again, I thought you waste more gas by doing that?

 

If it didn't save gas, why would it be there?

Stays off until AC or heat draws too much current or you step off brake.

 

I don't know, that's why I am asking...

 

I always turn it off. I suspect it's purpose is to allow Ford to show that, on average, mpg is lower and it helps Ford meet federal mpg standards. But for an individual, the savings probably isn't significant enough to offset wear and tear on the starter and battery. That's all speculation, of course, but I can't imagine it's good to punish the battery and start motor that way.

 

I leave it on and I think it does save a noticeable amount of fuel. It will stay off depending on whether you're running the AC or heater or driving at night etc. During the day with no AC on, it will stay off until the light turns green. With the AC on, it may stay off for a minute or so.

 

They are designed for it... Unwarranted speculation.