Gas Mileage

I bought a 2001 Taurus SES, with the reg. 6 cyl engine with 68K miles, back in Jan '05 and i was averaging about 23 mpg and could get over 350 miles out of a tank. I have put on about 8K miles, and recently the gas mileage has gone down, now i do have a lead foot, but i have driven from the beginning that way, and driving conditions have not changed much, i do mostly highway. Now i get under 20 mpg and can only go about 275 miles on a tank. I do change the oil regularly (2500-3500 miles), and have put in a new air filter. I have put in STP carb. cleaner to try to clean out the engine but it doesn't seem to have helped much. Does anyone have any suggestions as to what this may be about? THanks

First thing to consider is your driving habit. You can never expect to get good gas mileage with a "lead foot" or driving like a taxi driver. Drive the speed limit? Got your tires pumped up? 40 front 30 back.
Sit and idle at lots of stops and red lights? Anticipate ahead the red lights? Do lots of hard braking? Also, summer fuel SMOG mixes make fuel less efficient..

I owned a '93 GL
that mostly gave 30 mpg and at 55 mph on level road would get 32 mpg! I now own a '01 SES with the same 3.0 vulcan engine and at the very best can only get 27 mpg (55 mph with cruise). It might average 22/23
and thats country/village roads. I think the computers are adjusting the air/fuel ratio richer on fuel. That would keep down some other problems
that can arrise when trying to tweek out high mileage. This is a bad time to get poor gas milage. Our company has a few new Chevy & Ford vans and right now the the Fords are at 10/11 mpg while the Chevys are
getting 16/17 mpg (both doing the same thing) I love the Taurus and will get one as long as they make them. ( if not , then i'll buy a 500)
BUT poor mileage might force some to reconsider!