Nissan Repair: Please help, High Idle, vacuum hoses, oxygen sensor

Question

My bet is the intake gasket was installed incorrectly or it was damaged.  The intake will ahve to come off and have a new gasket installed.  I would purchase a code scanner on-line for about $65 bucks so I could read the code.  My bet is the oil or antifreeze taht is tracking into the engine is causing the oxygen sensor to set a code.  But, without knowing the code I am only guessing there.

Thank you for your reply, I also forgot to mention when I open up the oil cap at the valve cover (where oil goes into the engine) when the engine is running the car stalls and dies, It has a strong hssing sound at the intake manifold like its sucking air hard through the small tube. I have searched extensivly and found no holes or cracks. Its like its pulling excessive air into the valve cover. Thank you again for your help.  

Answer
Cory,

Most Japanese cars control the positive crankcase venting by controlling the amount of air that enters the PCV and taking off the oil cap will kill the engine due to too much air entering the intake.  Now, I would look over the engine to see where the new intake gasket was put on and be sure that all the vacuum hoses are connected correctly.  Check it out and email me back.