what is going on with this dang truck. its a 2016 suburban LTZ with 116k miles, just purchased saturday 11/25/22. sunday, the left driver side caliper fell off, then as of today 11/30/22 i cant accelerate without my windshield wipers coming on, multiple service messages,lights flickering, and getting stuck at 5000 rpms while trying to accelerate. i pulled over to the side of the turnpike and sat for about 2 minutes in drive, attempted to pull slightly more to the right and whole car dies. sat on the side of road for 3 hours waiting for a tow, at about 2.5 hours it decided it wanted to turn the hazards back on and not be dead anymore. i cautiously started it and it ran ok until my FIL tried to accelerate then this happens;

 

Welcome to the forum. No CEL? If not, then about the only thing I can think of would be to disconnect the battery for 30 minutes.

 

no CEL for that atleast, i only have two codes for the cats. (P0420,P0430
edit// i run a FIXD in my vehicle and checked my battery voltage which was changing pretty erratically, ranging from 11.2V-14.9

 

GM lets the computer control the alternator output so those readings aren't suspect.

 

Something to keep in mind,
Just because an alternator is not putting out a charge , could be because the computer is not detecting any or much of a load.. The charging system has to be requiring addl charge to get an accurate diagnosis..

Some systems have an alternator clutch system that require a higher RPM to engage the alternator pulley so the alt can begin to deliver a charge.