Americankill200

Hello recently I've had a issue where I get like a loud rattle coming from the engine. Opening the oil cap makes it even louder. I maybe though the pcv valve was the culprit so I removed it and started the truck without it and it stopped making that loud rattle. Could there maybe be a leak on the pcv Valve hose ? Wanted to check in it anyone has had this issue. I was also told there's a plastic underneath the valve cover that falls apart and causes this rattling sound.