does a 5speed get better mpg than an auto?

[RobertK]

I average 25mpg in my 325i driving to and from work. Acetone FTW!

[808BMW]

I drive a 5speed 325i and usually get 16-18mpg, But I drive a lot of long steep hills, and I floor it almost nonstop.

Don't o2 sensors make a big difference in milage? I'd try replacing that if your skipping on it.