OK my friend... this is what you want to do... you want to unhook all hoses from your valve cover, and make sure they all have clear ways for air to travel.. then unhook the elbows that the hoses hook into... again.. make sure the path is clear... If everything is clear, you might want to consider going to buy a valve cover gasket, removing the valve cover, spraying it with brake cleaner, and making sure the ports on it are clear of debris and gunk... the pcv system was designed to run one way, to us clean air from the air box to vent the crank case. But when this system is blocked, the system can run in reverse, and pull dirty, oily air from the crank case, and blow it into the air box... just make sure the entire system is clean.. your problem will be solved...
another solution you might want to try first... right before your next oil change, get a can/bottle of Berryman's B-12 Chemtool... this stuff is amazing... with the engine off, dump half of the bottle into the oil fill hole... then return the oil cap and start the engine... it WILL start hard, that is usual, and may run hard for a few seconds... let it idle for about 10 minutes... pour the remainder of the bottle into your gas tank...
The chemtool will circulate through the oil and evaporate, the vapors will rise and help clean out the upper part of the motor. Then drain your oil and change as normal... The chemtool in the gas will help clean your injectors and fuel delivery system... throughout the course of that tank, you should notice a difference if you were gummed up.
I wish you the best