vehicle stalls at idle and runs rough

Hi this is Dusty, I'm one of the auto experts on RepairPal's Car Genius team! Hey there! Sounds like you've been dealing with a real puzzle with your Envoy. It's great you've already swapped out some parts, but it's frustrating when the issue persists. That ticking sound and the squealing during shifting might be clues. It could be worth checking things like the belt tensioner (and pulleys while you're there), as they could cause those noises and affect engine performance. If the tensioner is compromised and is failing to apply the correct amount of pressure to the belt this could be allowing the belt to slip (which could be the squeal you've observed, and I've seen them create ticking sounds as well), and in turn preventing the alternator from generating sufficient power to all of the vehicle's electrical systems. The stalling may be related as well but could also be a failing or weak fuel pump given the intermittent nature. If you haven't already check for any DTCs that may be stored, this may point to a good starting point. There's a lot going on here, and a diagnosis by a competent professional will go a long way in pinpointing and ultimately resolving the issue, even if you prefer to DIY most of the repairs. Hopefully, you'll find the culprit soon and get your ride running smooth again! If you have any other questions or would like to help with finding a RepairPal Certified shop in your area, give us a call! 877-913-1554