BMW 320i se, 2001 model?

The onboard computer is showing that the car is producing 18-19 miles per gallon and before the car produced approx 25-26 mpg around town. Can anyone tell me what the problem could be. Someone said that the vacuum hoses could be loose or blocked. Is that correct?
Saif, November 2008


done
sounds like it usually caused by supermarket type fules they have to many addatives that block and clog modern cars best only to use big name filling stations

beamer bob, December 2008
link Click here to see other fixes for BMW 320i.