bmw 330xi 2004 shakes everytime I start it up

Hello, "shaking" is hard to determine when not addressing the car first hand. So many things can cause shaking. It can be an engine misfire with the vehicle sitting still. It can be multiple components if the shaking occurs when moving. Hands on testing is all that will determine what the source of shaking is. Yes, having no oil on the dipstick is not a good thing, any way you look at it. But may or may not be related to "shaking".

Engine misfire (shaking) upon start up then goes away is commonly caused by engine coolant entering the combustion chamber on one or more cylinders - as in failed head gasket.. Is coolant level getting low as well ? ... EVER see any white smoke (steam) from tail pipe ? *Hands-on* testing will be required. I don’t want to discourage you but the vehicle is getting old and tired - there are multiple possibilities for your concerns. Good luck with it!