My bonneville shakes, it seems that the rotations are only 700-800 per minute when in parking. It had more before, about 1000 or little over 1000. it is hard for the engine to accelerate. What can I do?

The first thing I would do is check to see if any codes are stored by the PCM. You need a scan tool for this. It sounds like ignition probs. to me, or the other possibility is fuel delivery. The idle rpm of 700-800 in PARK sounds about right.