Took my 2009 335i in for service a couple weeks ago. After the service I notice my gas mileage drop from a 19.8 average to high 13's to 14.6 mpg. I'm taking the car back to the dealer for a proper diagnosis. I don't have the long start problem associated with the high pressure fuel pump. Driving habits haven't changed either.

Any ideas why the gas mileage would drop so significantly?

 

Different gas?

My 335 never got better than 16mpg.

 

Nope. Same gas. Mine was getting close to 20 mpg.

 

I get around 14-16 but I have a JB3 in... 20-24 on the Highway.

 

what's a jb3?

 

Chip tuning afaik.

 

I was getting about 16, but my daily commute has brought my mileage up to 21.7mpg woohoo

 

lol
In town I get around 15mpg

with tune 13

but mine is 180kg heavier...

Did they install a new software?

 

I've got JB3 2.0 in mine and do a bit of spirtited driving. Average about 16 mpg

 

You got a 335? Nice!! thought you had the audi still but now I remember it was totaled..