Rough idling when cold, check engine light on

I have an '04 X5 4.4i with 120K miles. I had the 100K miles service warranty so it was pampered by the dealer during the first 100k. The check engine light is on (mostly steady but was flashing when idling is really bad), idling is rough when cold. Sometimes too rough that the engine dies or stops. When it's warmed up enough though it runs ok with a bit of hesitation at times. After it has reach "optimum" temperature (I guess when the needle points in middle), it runs great just like when I first bought it. Took it to an Autohaus shop (bimmer experts) and they say per their diagnostic tool all 8 cylinders have misfired at one time or another. I have replaced all plugs with recommended NGK plugs, oil and air filters, and the valve cover gasket (driver side only). I ended up replacing the ecentric valve shaft sensor as it was broken. Only mounting two bolts holding it to the engine. I still have the same symptoms, was discouragingly worst in the during the first 2 days after repair. It's gotten better but the darn check engine light is still on.

HELP! I am loosing faith on this X5 and am now thinking of getting rid of it .

Flying blind without the codes; have them read and post them here. Cylinder misfire could be anything; it's usually the symptom and not the cause.

Originally Posted by nesram4biz

I have an '04 X5 4.4i with 120K miles. I had the 100K miles service warranty so it was pampered by the dealer during the first 100k. The check engine light is on (mostly steady but was flashing when idling is really bad), idling is rough when cold. Sometimes too rough that the engine dies or stops. When it's warmed up enough though it runs ok with a bit of hesitation at times. After it has reach "optimum" temperature (I guess when the needle points in middle), it runs great just like when I first bought it. Took it to an Autohaus shop (bimmer experts) and they say per their diagnostic tool all 8 cylinders have misfired at one time or another. I have replaced all plugs with recommended NGK plugs, oil and air filters, and the valve cover gasket (driver side only). I ended up replacing the ecentric valve shaft sensor as it was broken. Only mounting two bolts holding it to the engine. I still have the same symptoms, was discouragingly worst in the during the first 2 days after repair. It's gotten better but the darn check engine light is still on.

HELP! I am loosing faith on this X5 and am now thinking of getting rid of it .

Sounds like my experience when the oil separator hoses turned to mush and split. Here are some details:

http://www.xoutpost.com/bmw-sav-foru...ause-pics.html

Easy to inspect and a low cost fix. The mileage on your X5 is in the ballpark for this failure.