Had a misfire on our 04 Escape 3.0 v6 last night, I want to say sudden but I think it's been happening but no codes. The CEL pointed to #6, looking at it the plug had backed out 2-3 turns. The plugs only have 9k on them and I know they were tightened properly. The plug next to it was loose 1 turn but the next one over was still tight. The misfire was still there so swapped it out with one of the good factory Motorcrafts. It feels like it still has a miss so will have to check the back ones when the weather allows. The question would be why the plug backed out and is that what caused the bad COP or did the bad COP cause the plug to back out? The generic Amazon front COP's have about 29k on them, the back ones have 9k when I changed all the plugs. I know most will say Motorcraft COP's but how about Denso or NGK COP's? Any experience with those brands in Ford vehicles?