Drunken Chevy

There are only a few ways this car can possibly be getting 11 miles per gallon. One is if you are consistently in the habit of letting it sit and idle for quite some time before you drive it anywhere, even a few blocks away. Two, it’s leaking fuel, or three, somebody is stealing it from your tank when you are not looking. My brother had a similar problem with sudden, horrible gas mileage, installed a locking gas cap, and the problem went away.