I was in the middle of a long road trip when I hit an incline and my car was struggling to maintain speed up the mountain. Then the check engine light came on and then went off again after a while. I continued having issues going up hills. I finally stopped and took my car to a mechanic who checked the oil and coolant and everything looked good. Then he took it on a test drive and said it blew white smoke out the back when he tried to go up a hill. He declared my engine toast and said I would need it completely replaced. My car is less than 10 years old and has been well maintained. I get oil changes on a regular basis, so there is no reason for this engine failure.

Update from Jun 16, 2022: The dealer has said that the engine failed due to a piston ring failure and that I need a new engine. I regularly have my oil changed, and I had my air filter changed last July.