Car started shaking randomly

Hi,

I know my O2 sensor is out on my bmw x5 its a 2002 3.0 with about a 150k miles car runs absolutely great drove from Oklahoma to Texas and not a problem nothing. But yesterday while we were driving the car started shaking randomly and did not get any acceleration. I pulled over turned it off and started it back up and nothing it drove fine have driven another 200 miles and no problem ....anyone think its a major issue?

Plus it makes a rattling noise when going over bumps or at low speeds but at highway speed the car drives like a charm

Thanks a ton