[Supershafts]

I have seen/heard my truck do it while idling at the pump

 

[Supershafts]

Observations from my truck on the AU flash - there shouldn't be any regen at idle however if you happen to be in a regen required state with a regen in progress when you come an idle state the EGR will remain closed (giving that fuel knock / rattle sound) and the latent heat in the DPF will make the exhaust hot enough to ignite stuff but there shouldn't be any fuel dosing occurring so the manifold EGTs will be 'normal' if you're at idle with sustained 1200+ manifold EGTs then something is wrong.

I was fueling up 1 night and heard it change tune, went around to the tail pipe and exhaust coming out under pressure and super hot.... like being behind a fan

That was the 2nd time that happened, the 1st time it happened i was talking with my friend for a little while truck idling and a/c on, we were in the path of the exhaust tip and all of a sudden it became blown out and hot, we both said holy sxxt we could cook off that sob tail pipe...no need for a damned portable bbq...just a grill in front of that