I went back to stock (my NA Z) and it runs and idles perfect. But there's a rattle somewhere. I will be double checking everything this weekend, but can anybody think of anything off hand?

 

Can you tell from where? My culprit was the center brake light. I had to wedge 2 pieces of foam between the plastic and rear glass. That solved it.

The only other noise came from my headunit. If I press in the console the noise stopped. Then it went away altogether....

 

my cup holder rattles sometimes.

my parking permit that hangs from my mirror rattles sometimes too.

is it interior or exterior?

 

man, I just read my own post and should've been more specific. I've installed my oem cats and oem exahust.. so it's somewhere within the exhaust system.. thanks.

 

loose heatshield on cats?

 

I had a rattle with my Borla hitting the rear stabilizer bar. Might take a look at that. If there is less than 1" or so of clearance when turned off, it might be hitting when it's vibrating at lower RPMs.

 

y-pipe upside down?

did you install the cat brace?