I have a 2005 530i 6 speed BMW which I bought about 2 months ago. The other day I wanted to pass a car and down shifted to 3rd, I noticed at about 4.500 rpm's the car seemed to hesitate a little, it didn't have that smooth acceleration you're so accustome too. So I've tested it in 2nd gear at the rpm range and again noticed a hesitation.

ANY IDEA of what it could be? Bad gas? the clutch slipping, injectors, a bad sensor?

I just brought in my car for the 60k inspection, oil change, brake and coolant flush. I'm sure the answere is to bring it to BMW for a diagnosis but thought I'd get some in put first.

Thanks.

 

Maybe the car only needs some driving on high revs for a while.
The previous owner may have driven it too carefully!?

Usually a M54 engine only starts to "live" at above 4,000 revs.

You do use high octane gasoline, do you?

 

I am not an expert on this engine, but is it possible that the variable valve timing system (VANOS) is changing the valve timing around that RPM? I just read where VANOS is continuously variable, so this may not be it, yet I have noticed a non-linearity in the power in my 4.4L as the RPM passes the 4-5K RPM range. It is most noticeable in 1st gear, but also in 2nd.

 

I buy Sunoco Ultra, I think it's 93oct. I've also guessed maybe the injectors need cleaning, I'll wait it out for now and next time I bring it in for the filter change I'll have them look at it.