I’m sure you figured it out by now but for future people searching for this problem, I just had the same exact issue and it was a cylinder 3 coil pack replaced it and runs great!!I am actually having the problem where it just cranks and wont start for about 3-5 seconds, but only when its been sitting over night, and its freezing cold out. Never had this problem with a newer vehicle in the past?
I used to have an 03 explorer that always started up on the first try, until it hit 150k. Then I bought my X (a monthish ago) and have been having this problem since. I want to take it to the dealer but I called him about it and he started telling me I am going to be charged! Not happy!