Ok, I had my Kinetix Plenum installed last weekend. Install was fine and idle is the same (no fluctuation or stalling).
Lately, it doesn't sound like it did before. Hard to explain it but it's sorta like a chain rattling/buzzing.
Is this normal? Could I have a leak? The idle is still the same as before, no dips or stalling.

 

is it rubbing against the strut?

may be reinstalled to tight (or to loose)

 

Hmmm, have to check. Also, can't seem to get the strut back to it's original position. Tried loosening the nuts on it, but won't budge.

 

I had the same issue with the strut tower bar. My nuts would not break loose (stop laughing, you know what I mean). After a liitle frustration, I hit it with some WD-40 and waited 20 minutes. Fixed the problem right away.

I though I had a rattle from my plenum too. However, throught powers of deduction, I figured out that it was my new driver's side cat.

 

Yeah, My passenger side cat (KINETIX) starting rattling really bad on decel around 2000 rpms about a week after I installed them. I got under there with a crowbar and bent the heat shields all to hell. No more rattle. Hehehehe!!