Hiccups/jerks/stutters during steady acceleration

[Lamanuzzi]

For the last two days, my 05 545 has been mildly jerking/hiccuping while maintaining a steady (under 40 mph) acceleration. From all I've read, it could be anything from a needed software upgrade to transmission to "bad" or low octane gas (which I didn't use). Before I try to take it into the dealership, I want to be as prepared as possible. I bought this car 4 mos ago as a CPO w/ 21K on it. My husband is deployed overseas right now and feel that as a woman, the dealership will try to work me over. It's happened before, so my apologies if my comment offends. Any advice or suggestions are appreciated.

[Me530]

I'd take it into the dealer, and see what their diagnosis is. Be prepared for the "can't duplicate" diagnosis. Often in this case it helps to take the tech out for a drive to show them. Has this particular dealership tried to work you over before? You could always try another dealership. You also may get more advice from our friends at E60.NET where they specialize in this sort of thing. :)

[bdkinnh]

Bad fuel pump? Water in the fuel line?

Is it only under 40 MPH, or does it do it while accelerating over 40 PMH?

[Lamanuzzi]

The problem happens only during light acceleration, under 40 mph. There is only one BMW dealership in my city, and I've had issues w/ them in the past. I can go to the 30 minutes away, just a bigger hassle. Yes, I'm afraid that they won't be able to recreate the problem since it doesn't happen consistently.

[sigma]

I see something similar on my '04 545i. A hiccup or two is a great way to describe it but I only see it 1-2 minutes after I restart my car when the engine is semi-warm. I assume at least in my case it's the engine management/valvetronic switching from a warm up mode to regular operation.