Ldub, your hole must be tighter than mine.

Seriously, I think my PCV valve would pop out of the valve cover before it built up enough pressure to hiss. It's that loose. Ah well, might be time for a new grommet...

You know, I thought of something that would pull enough air to hiss but wouldn't cause a CEL - brake booster hose!

Vendetta, yes some peoples' ability to pick out details is truly impressive. I've got a friend who runs sensory evaluation panels and I'm always amazed at her stories of how well the experienced panelists can pick out and identify the most subtle changes. I've tried it before just for kicks and can't tell one flavor from another while the guy beside me with the same two samples is identifying 40 attributes that are different.