Drop in MPG '04 325i

[acon]

My '04 325i had a drop in MPG from 19.5 to 15.1 last week. At first I thought it would be the drop in weather we had here in South FL last week but this hasn't happen in the past. Here's some basic info:

Milleage: 116K
Fuel filter changed 6 months ago
Spark plugs changed at 100K miles
Air filter/cabin air filter regulary changed
Premium unleaded always used

Car feels find driving. I don't think it would be the e-brake because there's no slugish feel.

Thanks!

[brettski]

Have you checked your air flow sensor, it may have a build up of crud on it, you can get specialised cleaners, and normally they aren't too hard to remove.

[acon]

Nope - didn't think of that. After my initial research I thought it could be one of the pre-cat O2 sensors (4-6 cyl) but this would be a good start. I'm going to hook up a code reader this weekend to see if I get any falut codes. Thanks brettski!

[Jack Dabsy]

BTW it will run happily on standard unleaded.