Ok so this is something I've heard for some time now and I wanna know if it's true or a myth. Does it take more gas to start a car than it does to sit idling for a few mins with the a/c on? I just figured I'd go ahead and get an answer. I remember when I was younger and running errands with my grandma she would always turn the car of if I were running into the store for only a minute and someone told me that it takes more gas to start the car than it does to idle for a few mins.

My grandma asked me if I remembered that when I was young and I said yes but I never found out for sure so I figured I'd ask. It's crazy what people remember. It's funny really.

 

I'd like to know the answer to this too...

 

mythbusters did this

they said it uses more gas after 10sec

 

Woah this is weird, I thought I posted an answer...well now I'd like to know what thread I posted my answer in lol

 

nevermind haha 2 threads from him on same topic.

 

Maybe it took way more gas back in Grandmas day when you needed to hit the throttle four times and pull the choke out all the way before hitting the start button...
Gary

 

Goddamn she isn't that old lol

 

Unless the car is cold, I don't see how it could possibly take more fuel to start it than to keep it running.

Even when cold, it may be enriched for a very short amount of time while all the sensors and FI stabilize. Notice this in my 2012 when starting cold mornings (<30F). Car will start just fine but rpm will fluctuate for about 20-30 sec.

Either way, when the car is off, fuel isn't being consumed. If I'm stuck at a train crossing or some other known extended stoplight, I'll typically shut the car off.

 

Anything over 30 seconds i waisting gas. Just think if your at a 90 second light everytime. That is a lot of gas that could be saved

 

^Yep that is why cars are now having that technology where they stop running while they are stopped.. Thought it was a Toyota advertisement, but could be wrong.

 

i just turn my car off every time, if i'm sitting in the car i'm usually waiting for somebody and that somebody usually lags haha

 

The fact that they make auto stop engines like the panamera seems to support that modern engines need little fuel to start.

 

You bought the wrong car if a table spoon of fuel is a concern.

 

i was just wondering if it was true. i had heard this before and today at work i decide to post about it.

 

I think people are just saving an extra crank on their starter by leaving it running but modern starters are more reliable than back in the day. Also the motor wear on start up can be avoided. Or if it is diesel its better to lea e it running.