I know I have an old car (2004 525i) but I love it! It was running perfectly except in higher gear around 2500 to 3000 RPM. It was subtle enough so that I couldn't tell if the roughness was the pavement or the engine. I determined it was the engine, because I could duplicate under slight acceleration on any road.


I did research .. could it be Vanos? Bad Gas? I replace the top side Oxygen (O2) sensors to no avail. (It was throwing O2 codes.) I researched fuel pump sending units, air filtration -- all of it. I wasn't sure where to turn, but finally found some older posts that described the issue perfectly ... the computer or DME needed to be updated! There is an SIB: SIB 12 08 05 that describes the problem.


Printed out the SIB, took it to my dealer and next day picked up my car after the computer update. They charged me one hour and the update made my car run/feel like new again!


I only post this because I hope it helps someone else. I wonder if the dealer would have had any clue to this solution without me having this data. The BMW forum(s) are fantastic for helping diagnose and save money!

 

Where can I print it out? I'm going to do the exact same thing.

 

I'm doing this tomorrow. I will let you guys know the outcome. Has anyone else done this? How much did it cost you guys?