Question about the hiss/rattle after installing HFC's

spearfish25

Not to beat a long dead horse, but I've noticed this hiss more prominently since installing my CBE. I first noticed it when I did my muffler delete. Then after switching to the full CBE it just continued. Of note, I'm using stock cats so the drop in back pressure with aftermarket accessories in general must magnify the sound.

Interestingly, I also notice the hiss when engine braking. For example, going down a parking garage ramp in 1st gear allowing the engine to slow the car...constant hiss sound identical to the deceleration hiss. The sound goes away if you give a little throttle or the revs drop low enough.

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2013 Cadillac V-Wagon, RIP Z