Cylinder 4 misfires and smoke from engine bay

[Joeclio182]

Hello, I had a fault come up showing a misfire on cylinder 3, I changed the spark plugs and injectors. The fault then moved to cylinder 1, I removed and cleaned the spark plug and now the misfire is on cylinder 4. I’ve checked the new spark plug and found that the spark plug was soaked in oil and the insulator had cracked. I have replaced the spark plug with a new one but still have a misfire on cylinder 4 and there is smoke coming from engine.

Any suggestions before I take it to a garage

 

[TheCAB]

Oil either gets in to cylinder passed the rings from the sump or down the valve guides. If plug is soaked in oil then unlikely to be valve guides. Check the compression on offending cylinder, could be a broken ring or excessive bore scoring/ wear.