First post, here it goes.
My name is Jesse.
"expired" ASE master tech
retired Army 11B
Conservative. lol i think

2012 Ram 2500 cummins deleted, with exhaust and generic tune.
1972 GMC C50...

I have seen exhaust leaks do this before on TBI setups. I have held off posting because honestly the IAC value is throwing me off. but something to look for. usually near the O2 sensor.

Btw this...