1997 528i engine light issue

I just purchased a used 97 528i with 63K miles on it. When I first test drove it the engine died, but the dealer thought it was a bad gas gauge. So when they replaced those, they said it was fine. I test drove it again with no problems. Bought it on Saturday. On Sunday drove it a little further and then the engine light came on. It had a hard time accelerating. So the dealer picked it up, and said it was a CAM sensor. They replaced that, then today when i was to pick it up the dealer drove it again and it had the same problem! Does any of this sound familiar to anyone?
thanks