Car has 53K miles, one owner and well maintained. The car is possessed.

What is your question?

One day the car starts and runs great then the next day I try to start it and the battery light stays on, car runs terrible and smelly exhaust. I have replaced the battery, alternator and had it in the shop for 2 weeks. Mechanic could not find the problem, is not setting a code, will run great for days then out of the blue it acts up again. I can't trust this car to leave my driveway. Any ideas?