engine stalling

What is your question?

i have a 2005 dodge magnum se.. recently i took it to the shop for a routine service, and when i got it back its been giving problems.. it seems to runs just fine but when i first start it, if i dont let the engine temp warm up it tends to stall, and the check engine light flashes.. i took it back and they said it was because they didnt recalibrate something.. and they "fixed" it free of charge.. but the next day it started to do that again.. what do u think the problem could be? and how much should it it to get it fixed? thanks in advance for your help