The acceleration thing sounds normal for an M104. The engine has variable timing on the intake camshaft and also resonance flaps inside the intake manifold. As these gadgets are adjusted while accelerating the changes in torque produced can be felt as fits & starts in the acceleration rate. I certainly notice this in my M104 engined 124 car, and also recall mention of it in some auto magazine reviews from back when.

Long crank is a tougher diagnosis over the internet. One common service item on the M104 is the fuel pressure regulator. Quick & dirty test is to pull the vacuum line from it and check for presence of gasoline and/or strong odor of fuel.

- JimY