98 Sebring V6 stall and P0455 intermittant
 

98 Sebring code P0455 stored and CEL on. Actron scanner shows all systems OK with engine running and being driven with light on. Cleared code with scanner, drove approximately 10 miles, CEL tuned on while stopped at light, checked code-- again P0455, but scanner shows evap system check as OK. Cleared code put on new gas cap (easiest fix) drove 10 miles no CEL, next day driving at slow speed in traffic, engine stalls, CEL on and again code P0455. Examined hoses, all appear OK. Am I right in assuming the next logical step would be to replace the purge valve? As this is a "massive leak" code and it is not consistant (returns to normal operation after restarting and driving but light stays on) that it has to be something that cycles open and closed? Anything else in the evap system open and close that could also cause a stall at low engine speed and set this code. Any help appreciated, this is my daughter's car and a stalling condition in traffic can be dangerous. Repair shops have diagnosed and replace MAF and misc other unnecessary items.