Last weekend my 1995 525im traveled 200 miles North to NH and returned 28-29 mpg by the trip computer. After being parked for the weekend the retuurn trip involved three hours of steady driving rain. A few hours into the trip I was playing with the MPG function when I noticed it was low, like 22-23 at best highway conditions remained.

The O2 sensor is pretty new, plugs maybe 15K miles. I'm wondering if the air filter element could have gotten soaked in the driving rain, any other thoughts?

Thanks in advance,

John in CT
1995 525im w/ 91K miles