I have a 2008 f150 and i was having a major misfire and the truck was running super rough... i changed all the coil packs and the truck improved but still was running rough.. almost like it was starving for fuel so i checked the codes and seen where i had injector issue on cylinder 4. so i took the injector from 4 and replaced it with number on and now truck will not start. i tried changing it back but nothing the truck will turn over but will not fire.. any suggestions