welcome to the forums. theres alot of things that could cause that. allthough kinda rare, its posable your rocker arm might have come loose or is wore for some reason. ive seen them jump off a valve stem. also it could be the lash adjusters can become clogged or varnished and not moving corectly. they have a plunger that can get clogged. they are kinda like the old lifters with a built in pushrod. you`ll have to pull the valve cover to check it out.the rocker should not be real loose. i would check it with a compression guage first. i would have thought plugs,wires or coil to begin with, but youve kinda ruled those out. i would still check to see that you have good spark there. there is a online motor manual above the posts in the sticky section to look at, but you might want to let a good mechanic check it out. could also be a bad valve or fuel injector. double check the spark plug is tight, and the wire is on good. there are bad new coils too.
__________________ goina hundred in a 55, and i dont know why..
some things were just meant to be..
05 V6 auto, torch red, basic,:cool: a few mods
06 V6 stick, vista, premium (g/f`s car) | 
2005 Mustang V6 Cylinder 4 Misfire 
