About a year ago I dropped a 4 bolt 350 with 50k miles into my 93 Silverado. The truck also has a new Jasper transmission with about 15k miles on it.
The truck Idles fine, but Lugs really bad when driving at low RPMS.
Ive ran Injector Cleaner.
Changed the fuel filter.
Had it re-timed.

It doesn't seem to do it when it's cold or has sat overnight. But after I start it up in the morning and run it for about 10 minutes it starts doing it badly.

Could this be the TCC sensor? Any other ideas?