I have a 1997 Honda Civic EX, after from going home from out of town. My check engine light was flicking on and off. The car all suddenly started shaking. When I got home, I replaced new park plugs and took it for a test drive and ran well. After for a couple minutes same thing happened again but just that now you can also hear a CLICKING noise coming from the head. I rechecked all the spark plugs and found out that it was probably miss firing. The second park plug from the left also has oil on it. If that is the problem or something else let me know what to do to fix it!

There is a round oil seal between the cam cover and the cylinder head at each spark plug. Try snugging down the covers bolts a little (those studs break easy so be gentile)and see if any were loose. If it still leaks those seals and the cover seal will need replaced.

I see. Thanks

This link will help:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-13.html#post2561356