At operating temp. Truck sputters and stalls when at a stpp.

Replaced iac, tbs, crankshaft position sensor and the fuel pressure regulator. Cleaned the throttle body and replaced the throttle body gasket. Did the "cigar test" to check for vacuum leaks. Exhaust is a little louder than usual. Some carbon around the connection between the cat and muffler. Thank you for any advice you may have.