As a mechanic, you can't get paid until you fix it, and you can't fix it until you diagnose it, which means a quick diagnosis means a quick fix which means a quick payout. If life was always this easy! This automotive video will show you how to troubleshoot and diagnose a 1999 Mercury Village, 3.3L, with 150,000 miles on it. The chief complaint is the CEL (check engine light) comes on and it runs like it has a misfire. It feels like a steady consistent misfire, which is code P0304 (Cylinder #4 Misfire). Watch the video for the simple process of finding the solution to this troublesome problem.