Why on a 1999 ford f150 Triton 4.6L has no engine check light on run rough and smell like rotten eggs?

A 1999 Ford F-150 Triton 4.6L running rough and smelling like rotten eggs likely indicates a problem with the catalytic converter, which can cause improper exhaust flow and lead to a rich fuel mixture. The rotten egg smell is typically sulfur from the catalytic converter not functioning correctly. If the check engine light is not illuminated, it might be due to a malfunctioning sensor or a failure in the onboard diagnostic system. It's advisable to have the vehicle inspected for trouble codes and exhaust system issues.