10% drop in gas mileage E46 - Why?

[SteveC]

I have a 2000 323i (automatic) with 48K miles. I've always gotten 34+ mpg at my cruising speed of 72 mph. It has abruptly dropped to about 30.5 to 31 mpg. The engine runs smoothly. Anyone have the same problem? I have an extended warranty.

[Ocean02]

Did you recently have the engine serviced? Honestly, 30 mpg is not bad. I have an 02 325i with 78k miles and I get average of 25 mpg city/freeway.

I would imagine that an abrupt drop like you mention would have something to do with computer compensation, if you are not noticing any power losses, etc. Have the codes run at your dealer if it's still under warranty.

[peterkulesza]

are you in california? it could be the gas u use....