Hey guys on my el xr6 when ever I turn my car off my pcv valve keeps sucks for a couple seconds. iv replaced the valve, gromet, hose. But nothing I do seems to fix it. Any ideas? I could possibly post a video of it doing it if anybody needs

run engine-remove pcv and block with your finger and have some one switch engine off - possibly loosing vacuum thru "brake booster" or heater control vacuum feed