Hi Gene, do you have a VIN? I can check which coil should have come with the truck. The brown boots are about 1/2 longer than the black boots. Are you only getting a misfire on #6 Check the other cylinders that don't have issues and see what they have. Always try to go with Motorcraft on the 5.4 coils if your customer's budget allows. We have had issues with aftermarkets in the past. Good luck, Richie

Richie Salerno
Manager/Service Advisor
New Jersey Auto & Truck
Paterson, New Jersey, USA