i have 97 gran prix with a 3800 v6 series 2, every now and then it wont idle. i noticed it has blown oil out of the valve covers onto the intake and when it is acting up i can take the oil filler cap off and it will clear up and idle smooth. so i figure it is a clogged pcv valve, but there is none on the valve covers and i cant see where one is anywhere else. could it be something else? and where would i look for it?