I recently just installed my Nismo intakes on my Z and later on figured out the rattling i was hearing, was the CAI heatshield rubbing up against the AC Line. It almost cut a hole clean through it before I caught it unistalled it and made a few cuts. I am still however getting horrible squeaking noises around corners and on uneven surfaces. I pinpointed the squeaking to the ac line because whenever I get up in there and wiggle the damn thing, its the same squeak thats driving me nuts! I just got back from the dealership and they said it was impossible to be loose because it is dirrectly bolted to the engine..

 

What brand is your CAI heatshield? And please post up some pictures so we can try to help.

 

Its a nismo CAI (with nismo heatshields). I circled the points that are squeaking in red. I know because I can phyisically wiggle the parts a litle and hear it. Its not so much the shields that are the problem. Check out my pics and tell me what you think. Im willing to do anything to get rid of this squeak.. hope this helps