Is this a valve cover gasket leak???

Also could this cause a running lean code 44?

I have been tryin to narrow my problem down since the beginging and its been one thing after another.
**Brief summary**
Car was running rich
Changed bad fuel pressure regulator
Car started running lean right off the bat
Found oil on spark plugs when replacing
still running lean after codes reset

 

Was the oil on the threads and outer insulator, or on the electrodes and inner insulator?

External oil can be from a leaking rocker cover. Internal oil is more likely from a leaking intake, which might also explain a lean condition.

 

Does the vehicle blow blu smoke even when its warmed up especially under some throttle? If so, they you have blowby possibly happening as well, from either worn cylinder rings, or scored cylinder walls.