Sarah wrote:

> The dealership did do diagnostics which should have shown a clogged air
> filter.

Actually, this is not true. Not unless the air filter is pretty much
blocked. Electronic diagnostics is a simple search for trouble codes.

The only thing that they could come with was driving style.
> But I cannot imagine a 8 mpg difference from the expected 30 mpg city.
> My next step is to have the oil changed.

You may want to invest in a tune-up, too. Maybe have them check the
brakes, while they're got the car on the lift. Even with just 14K
miles, you may be well served by having a technician give the car a
thorough mechanical check.