My wife had stepped in to the assisted living center that my mother in law lives in while I opted to stay in the car and listen to comedy on Pandora. While waiting, I decided to watch the MPG-o-meter and see how long it takes for it to go down while idling.

It goes down .1 with about very 3-4 minutes of idle time.

I hope this helps anyone that has thought the same.

 

How quickly it drops will depend on a great many things, including in particular how recently you've reset the the meter (the trip odometer) and what sort of mileage you were getting before hand.

That said, it's certainly true that idling (when the engine is warmed up) does not consume a great deal of gas. That said, it's not really necessary to leave the engine running just to listen to the radio for a few minutes or a half an hour, assuming you don't have a thumping great subwoofer going or something of that sort.

 

mpg-o-meter raise and drop speeds depends on when you last reset. for instance, right after you fill up and reset, your meter will drop a lot more drastically than say when you've already traveled 50 or so miles.

 

shame on you, go see your ma-in-law! LOL

 

I would leave it running LOL. A LOT of posts on members leaving the car on with stock radio just while washing the car and ending up with a drained battery. Fits run close to the bone on electrical battery power is not worth the risk of having to get a jump when it dies.

 

I agree with the strategy of leaving the car running while on a visit to the MiL. Speedy get-away is critical.

 

yah, i too noticed that my mpg rised quickly when i reset it after a recent fill-up.

all winter long it showed 31.0mpg, but now with no difference in driving, a/c on all the time, showing 32.8mpg...thanks to non-winter gas.