Hear the pfuff sound and smell exhaust gasses, preliminary inspection cracks in the exhaust manifold at the upper bolts. Sure we will go to the junkyard and pop on a new manifold,but any clue why it is cracked?
The exhaust manifold is made from cast steel. The head is made of cast aluminum. These two materials expand and contract at different rates when heated up and cooled down.
Over time, the more brittle material fails first from this heat cycle.
Toyota’s had this same problem. Their fix was a beefer exhaust manifold with a more open heat sheild.