[gtochism]

if you have 25lbs in one cyl, and it did not come up when you added oil you have a bad valve in that cyl. just becouse the pcv rattles doesn't make it ok. could be crud behind the spring in it. make sure it is the correct one for your year engine. check for good vacume by putting your finger on the end of the valve while the engine is running. i've always used the rule "if the variation between cylinders wasn't over 15lbs" it was ok for a stock engine. past that you get a rough idle. pull the head, valve job time.