I have a problem with my Z and I need your help finding out what it is...please. I think the problem is somewhere in my exhaust system but to give you a bit of a background on it, I have an 03' Track w/ Nismo intake, headers, exhaust, and Crawford cats. Anyhow, whenever I decelerate and sometimes even accelerate through about 2,250 rpm and again at 3k rpm I hear a 'rattle' coming from the bottom of the car. I thought it was a loose bolt or something similar but I just got back from a shop close by and they said everything was 'tight' and that my problem was internal and most likely the 'resonator'. Does this sound accurate or does it sound like I have a leak? It sounds like a piece of metal vibrating and it is very annoying. I don't think i'm losing power but i'd like to get it fixed asap. Any ideas on what it is and what I can do? Thanks for listening...

 

While they were under the car did they bang on the exhaust pipe and muffler(s) to see if anything was loose internally or did they just guess it might be the resonator? Did they start it while it was on the lift and then rev it to see if they could duplicate the sound you're hearing?

I think a closer inspection, past checking the tightness of the nuts and bolts, might be in order. My .02c worth.

 

Yeah, i'm definitely getting it checked out again. I just want to have an idea of what it could be so i'm ready to make a decision once I here the diagnosis. Thanks.

p.s. I actually reposted this thread in the engine forum so it can get more exposure.