How much mpg will a car loose if its ten yrs old?

Question

I have a ford focus 1.6 LX 16v zetec engine.

Answer 1

Age generally has nothing to do with the loss of mpg's, typically the size of the vehicle & engine does. Also how good of condition the engine is in, and how well maintinence has been done, spark plugs, air filter, etc, can make a big difference too.

Answer 2

time doesn't decrease the mpg.. the size of the engine does. basically, the bigger car you have the more gas it will use.