Agree with others. Averaged about 28mpg in my 94 e320 from Dallas to Fairfax, VA; get about 22mpg every week to and from work. Try the usual things: spark plugs, air filter, etc. Use ONLY the Bosch plugs recommended in this message board; a quick scroll down will provide all the info you need about the engines need for the right plug - reject the idea to install platinum plugs..
Seats are near perfect for me; bottoms firm and long enough to provide thigh support nearly to the knees. Only my long gone Volvo 780 has better seats.
regards,
Mark