5 to 9 mpg. on 2007 Chrysler Town & Country

I get 5 to 9 mpg, and yes, I KNOW HOW to figure mileage. I get between 130 and 190 miles from a 20gal tank of gas. A 2000 Chev Venture produced 420 mile to a 20 gal tank. Yes, its tuned up. Yes, filters are clean. Had fuel pump replaced. Mileage got worse. No hesitation, no evidence of rich lean / fuel, no other performance problems. If I constantly re-set the avg mpg computer thingy, I get around 330 miles per tank. If I re-set avg mpg ONLY after refill gas tank, it goes back to around 8 mpg. Avg MPG is accurate to +/- 3 mpg.

by in Lacey, WA on April 25, 2012
1 answer 2 comments
ANSWER by on April 25, 2012
you need to have fuel trim ck'd while driving. you may have a bad fuel pressure regulator which will make car run rich but not detectable by the eye.
COMMENT by on April 27, 2012
dealerships wont check it. They say, "the computer does not say the fuel trim is bad". Would not "rich" running show up as some kind of performance problem? Isnt the fuel pressure regulator contained within the fuel pump, (replaced about 3 months ago).
COMMENT by on April 27, 2012
YES IT IS BUT A TEST OF THE FUEL PRESSURE WOULD CK THAT. IF FUEL TRIM IS GOOD THE REG SHOULD BE. WHAT IS THE INJECTOR CYCLE TIME AND DURATION