I'm not overly familiar with Rotella oils but from what I understand it's a diesel engine oil which can be used in gas engines, but it's still formulated for diesel engines. You should be using a 5W30 or a 10W30 formulated for gasoline engines. I don't think your engine noise is from using Rotella oil, but strange things happen so I wouldn't rule it out.
The engine noise is probably more related to your misfire issue.