Hi everyone, I purchased a 525i 2004 e60 BMW cheap off a friend who couldn't be bothered with it anymore, it failed a warrant of fitness for oil leaking onto exhaust, he was told valve cover gasket and rear main seal needed replacing, it was clear to me the rear main seal was fine so I replaced the valve cover gasket and cleaned the engine bay and the leak is fixed, however in the process of fixing all of this the car has thrown a p0444 fault code Evap sensor, I have tested the evap sensor and it's compelely fine, the car was running perfectly before the valve gasket was replaced but has since started surging between 1500 and 2000rpm whilst driving at a steady cruising speed, I have checked for vacuum leaks and cannot find any, all plugs seem to be clean and all coils are testing good, the injectors are all good aswell, can anyone give me any ideas what could be causing this problem as I'm running out of money for repairs and like explained above the car was running perfectly before fixing valve gasket although it was leaking, any input would be appreciated, thanks in advance

 

When you say it was running perfectly before the gasket change that implies to me that it's not running perfectly now. So in addition to the P0444 is it also not running well? Or is it running well, it just has that code now and did not previously?

 

I dont think the p0444 code is affecting the way that it runs now, its surging whilst driving between 1500-2000rpm the needle basically jumps floats between the revs, it was not doing this prior to valve gasket repair

 

Yea not running perfectly now at all in addition to the p0444 code

 

Yet to check trans fluid level could this be a potential cause of the surging?

 

My BMW E60 525I 2004 also have this code p0444 and its running very fine, so am suggesting that this code has nothing to the with how the car is running. Several other reason might cause your car not to run very well like the PCV or CCV, Coils most especially. From what you said BMW E60 2004 525i operate on M54b25 Engine. So check your Air intake, coils etc.