burnt03

I had the same issue on my 07 4.8L. I had AC delcos, torqued to spec and they came loose about a week later (2 or 3 of them). Did what you did, the nice and snug technique, and they've been good ever since

This is probably a long shot but worth checking the easy stuff first... I was having the same issue with my Dodge Caravan . Turns out that my auto trans fluid was a bit low and causing it to lock up and stall the engine out. Topped up and it's been good for months. Good luck