Rough start and shaking?

Goodmorning! I purchased the vehicle approximately 2 months ago from an auction. I made the 5-mile drive home with no issues. No lights on the dash. I parked it in the back of my house which has a 12-inch hill, so the car was leaning on the driver's side. When I went to turn it on the next day it sounded horrible, and the check engine light was on (solid). I put the reader on it, and it gave me misfire in cylinders 2 and 4. I proceeded to take out the spark plug wire from cylinder 2 and found it was full of engine oil. The spark plug was soaked. I checked the other 3 but no oil. I opened the valve cover gasket and found the rubber seal to protect the spark plug was broken. I changed it, the check engine light went away but the shaking continued. It would always shake but the check engine light wouldn't always come on. One day it did, so I changed the spark plug wires, it seemed to work because it turned on great with no shaking. The next day it shook again, and the check engine light came on, so I turned it off and tried to turn it back on, it cranked but wouldn't turn over. The code again was misfire cylinders 2 and 4. So I changed the ignition coil. That seemed to work as the car turned on with great power with no check engine light. The next day it began to shake again but the check engine light has not come on yet.