P0300 code misfire

You changed the crank sensor, but did you do a crank position relearn after you changed it? If not that could be the source of the P0300 code. Each sensor is made a little different and the ECM needs to learn where the new sensor actually reads the crank notches. Without that the timing and injection can be off enough to cause problems.

Rattles and sluggish almost sound like a failed converter that is blocking the exhaust. For that you would need to do an exhaust back pressure test to see if you have an issue there.

Did you do a crank sensor re-Learn? As I said, if you replaced that sensor and did not use a scan tool to do a re-learn it could easily be the cause of this problem and the reason you are getting the misfire codes.

You need a bi-directional scan tool. In the tools menu will be the option to do a crankshaft sensor reset and test. No other way to do one as it means you are erasing the stored data for the old sensor and the ECM learns the new one. On some it is not needed but if you still get the codes it is one of the first items to reset.