Acceleration lag, 650i convertible, standard shift

Lag is most noted around 2500 RPM's, in 2nd or 3rd gear while attempting to accelerate quickly. BMW service has cleaned the injectors, replace fuel, checked mass air sensor, valvetronics test per TSE, update DME per measures plan, check energy diagnosis.

I previouly owned a 2007, 335i convertible, with standard shift. I was very pleased with the way that engine responded. Just a little small for long distance travel. Since this is my first 6 serries, I wonder if my expectations for the V8 are inflated.

Has anyone had the same or similar problem? Any solutions?

i think they designed it that way on purpose..

I don't seem to have that issue with the same configuration vehicle. Can you give some further detail on the lag you are feeling? I mean, some people are more sensitive than others...That said, I've hit it pretty hard accelerating out of second to merge onto an awkward freeway onramp near my house, and I've never noticed a lag. Does the engine flutter for you or does it simply feel like you are getting very low torque?

The only other time I've heard of a similar issue (and this is a long shot...) was in a neighbor's 645. His was an issue with the air flow sensor, but it sounds like you've got that covered. In that case, however, he only got about two or three symptomatic lags before the whole thing failed and had to be replaced.

The lag is most apparent when I hit it hard at aound 2500 RPMs, mostly in second gear.
There is always a lag between pedal push and acceleration, but not the hesitation described above. It feels like the fuel system is loading-up.

I am driving a similar equipped car today and hope to be able to make a comparison. Service department has been considerate and communicated with BMW engineers. I hope this is not the way all 650 standards shifts respond.

mine doesn't have this issue - good idea with the loaner, which will hopefully perform as expected. good luck with the trouble-shooting and hope they can find a fix.

Did you ever resolve the hesitation issue?

I have a similar problem on my 2006 6sp. The rpm will occasionally drop 500 rpm under hard acceleration somewhere in the 2800-3800 range and then catch up again. It is like the engine stops for second. I see no codes on my Peake meter. And when I took it to the dealer he could not make it happen. Intermittent problems suck!