Spray brake clean or carb cleaner all around and see where the vacuum leaks are??? I use silicone on both sides of my intake gasket.

where did you install the sensors for the O2???

Do you have another carb to try I think this one is wacked?? was it new
or jerry rigged by someone??

You probably need a faster.

Try holding you hand over cab to see if it idles better



Maybe ulta lean had been your problem all along.