Michelle.S wrote:
I don't fret over my MPG, but I do monitor it because a sudden drop can indicate a problem that might be resolved before becoming something serious.
My guess is if you are concerned about fuel economy for the reason you say, it will more likely cost you money than save you. It’s very unlikely that you will ever have anything serious go wrong with your engine. The chance of something happening to it that will cause the mileage to drop off significantly before causing something serious to happen is almost zero. The chance of seeing your mileage vary on the other hand is not that unlikely. So what are you going to do if suddenly your mileage drops 15% and you can’t come up with an explanation? Bring it to the dealer so they can change your air and fuel filters, tell you everything checks out and charge you $500.