On cold mornings(about 10 degrees) my 4.7L Dak starts quickly and runs fine for about 2 minutes. It then develops a miss until the engine starts to warm up then the miss goes away. When it's not so cold the miss never happens. The plugs (Autolite 5224) are new and the coils are properly seated and connected. No engine codes show up. What gives? Is one coil going bad? If so, how can I test the coils to find the bad one?