People have posted that unmetered air due to an open air crankcase breather may cause a lean condition; however, I am not certain this will occur. A concern of mine with the stock crankcase ventilation system is that oil from the crankcase vent may carbonize on the throttle body and intercooler. I'm leaning towards a K&N breather filter and plugging off the vent to the air intake tract. Please convince on what to do or what not to do. Thanks.