View Full Version : Reduced gas milage

12-15-2009, 01:43 AM
1985 Mercury Grand Marquis, 302 V-8 engine, starts and runs good, but over the last couple of months, gas milage went from about 19-20 mpg on the hiway down to around 10-11 mpg. What are some of the most common problems that would cause this loss in efficiency?

12-15-2009, 04:24 PM
Hello slowpoke,

There are a couple of areas that are worth checking. You could get one of our Chilton manuals (Ford full-size #26360) for reference. When is the last time the vehicle had a tune-up? You would also need to check for any fuel leaks and detached vacuum hoses.