Has anyone experience a rattling noise after installing the Magnaflow Catback System #15609 after a cold start? It only rattles when the engine is cold and when I start in rear or drive but not at idle. I am wondering if something was missed during the install but everything looks good. The system is not touching anything, although the curve of the rear pipe is a little less than a half an inch from the spare tire. I used the clamps that came with the kit vs. weiding.

Any suggestions?

Thanks in advance.