[shorod]

If you can get your car to a local auto parts store that reads codes, have them read. Since you mention your check engine light was on, you should have some stored codes. Most of the chain parts stores (Autozone, Advance Auto parts) will read the codes at no cost. Get the codes and post them back on here.

Since the light was flashing, they computer was reporting a problem that is dangerous to the emissions system.

I would imagine that since you changed all coils and plugs, you would notice is the air intake hose is disconnected, but check it again anyway and make sure it is tight. Also, do you have a K&N or other oiled air filter? If so, there's a good chance the oil has contaminated your Mass AirFlow (MAF) sensor which, in extreme cases, can cause the symptoms you describe, especially if you recently oiled it. It is possible to clean the MAF, but one must be very careful as the wires are quite fragile. Also, make sure the electrical connection to the MAF is good.

Check over the engine compartment for rotted, cracked, or disconnected vacuum lines.

Are you confident the spark plug was actually covered in oil and not in fuel? Do you still have the plug? If so, is it still wet, or has the liquid evaporated? If it is still wet and definitely oil, then you probably have bigger issues that new coils, spark plugs, MAF sensor cleaning, etc. are not going to fix. You may have blowby due to scarred cylinder walls or bad rings, or you may have a cracked block or head gasket. What does that cylinder have for compression?

I would suggest you check all the vacuum lines and the air intake system. If that is all fine, get the codes read and posted here.

-Rod