I am have the same problem i just got the heads repaired from a crack and it started stalling so i brought it back and the check engine light came on and it was the throttle body so i replaced that and it still stalling (reset pcm to) then i read the fuel injectors needed to be cleaned so i did that and after that then stalling got worst brought it back to the mechanic and he drove it and the thing never stalled once and i cleaned the Mass air flow Sensor to and i am not getting any error codes at all. i am stuck and dont know what to do. O yes and i had the timing chain replaced