red44

Yup. Agree with the other posters, nothing to be concerned about. Annoyed yes, but not concerned.

I had a truck with cats that sounded like a maraca band at stoplights until I figured out the heat shield was half-rusted and vibing like a tuning fork. Your description is exactly what mine did—random metallic chaos that’d come and go like my motivation to fix it. Since it’s the cat area: Heat shield: 90% chance it’s that stupid shield rattling. Get under there and wiggle it—if it moves, either bolt it down tight with washers or rip it off and yeet it into the sun. Internals: If the shield isn’t the culprit, the cat itself might be crumbling inside. Tap it with a rubber mallet (gently!)—if you hear loose chunks, congrats, it’s time for a new cat or a hypothetically hollowed-out one. Exhaust hangers: Check if the exhaust is sagging and tapping the frame. A $5 hanger from AutoZone might save your sanity. Either way, glad it’s not the engine/trans! But fair warning: that rattle will slowly drive you insane. Mine got so bad I started hearing it in my dreams. Good luck!

Hey man, that’s rough—sorry you’re dealing with this right after buying the truck. I’ve got a buddy with a 2020 L8T who had similar gremlins (his threw a P228C last year). Turned out to be a wonky fuel pressure sensor, but his dealer dragged their feet for weeks blaming “bad gas” first. Couple thoughts: The fact the code cleared itself is kinda sus. Could be a fluke, but these trucks are notorious for electrical gremlins. Make sure they check ALL the wiring/connectors around the fuel system. My buddy’s truck had a chewed-up wire harness (thanks, rodents…) causing intermittent chaos. The parking brake warning + noise? Maybe coincidence, but have them double-check the rear brakes anyway. Could be a seized caliper or debris—would explain the rubbing. Lemon laws for used vehicles are hit-or-miss depending on your state. If they can’t fix it after 3-4 tries, then you might have a case. For now, document EVERYTHING. Texts, service slips, even a video if the noise comes back. If the dealer gives you the runaround, call GM Corporate directly. Sometimes lighting a fire under corporate gets things moving faster than the local shop. Hang in there—hopefully it’s just a sensor or something dumb. Keep us posted!

Did you find it online? I know someone who's in the market for a Ford bumper

Agree, never had any issues with Bilstein shocks before. I was a Rancho guy for a while, but they never really lasted longer than 2 years.

I agree, mostly, but I used to have a 2011 Silverado with crap suspension. The first time I ran into trouble it was all still under warranty, so no issues there, but it happened again a couple of years later and I went aftermarket because it was way cheaper and all the problems mysteriously disappeared. Probably different these days with newer trucks though.