What was the reason you had the rebuild? When I had an issue
with my truck, (a cam issue), somehow a bunch of fuel was dumped
Down into the cat converters. Then the repAirs were made, which took months. When I got the truck back after the repairs, I drove for a mile or so, and the cats plugged up completely. Backfiring and no power.
If you want the whole story search "tick tick oh no"
It was a mess.
Hope you figure it out!