I wouldn't say common but have seen it happen well under 100,000 miles.

Forgot to ask: Do you run a lot of fuel additives as they can contribute to early converter failure.

2002 X5 3.0
2004 325i

Mad Mike,

What did you find was wrong?

Hey just as an update, I am still working on the problem. and no I don't run any fuel additives. I should know more as far as a solution to my problem goes tomorrow.

ok so I took it to a bmw mechanic who scanned it and the only problem was the mass air flow sensor so I went and bought one and put it on. no result with my current issue. does it take a certain amount of miles or time to learn the new sensor?

Nope, should be better immediately.

If it was MAF disconnecting the power to the old one should have improved idle. Same goes for new one.

what were the actual codes that he pulled?

status update. clutch fan needs replacing (it's almost seized) however they still can't figure out my power loss. luckily e mechanic has one so he knows what it should feel like vs mine. Currently it is not throwing any codes at all and idles great no sputtering, normal temp range, shifts fine, no smoke or smell, just lacking a roughly 40% performance amount. I have an appointment for July 10th for some down time in the shop for repairs. I will keep you posted.

Your Tech didn't notice a bad clutch fan when he was scanning it? I would stay away from him and go somewhere else.Remove or replace the fan 1st then see how it runs