Tensioner Losing Pressure
 

Are the chain tensioners supposed to maintain pressure, even during extended periods of the car being in storage, or is it normal for them to lose pressure over time?

It's pretty normal for them to lose pressure after sitting for a short bit of time. My Boxster clatters when starting up, and my Kawasaki Concours 1400 motorcycle does the same thing.

They have springs in them so and I don't recall them having a check valve. I replaced 1 of mine when we did some engine work and it fixed the cold start chatter.

There are newer versions of them as well that are "better" Replacement is a breeze to do.