so my car has recently started to stall while driving and occasionally while idling in traffic. The ac was on the first time it happened but not for the last 2 episodes. The check engine lights on but only for the cat. Could this be the root of the problem? I've tried cleaning the mass airflow sensor, still happened. Could it be the throttle body? Please help, at a loss right now.

 

Could be a clogged cat. Try reading the codes one more time......

 

When it stalls, does tacho hand drop to zero right away? If that is the case, this can be the ECU relay.