I did the coil pack, the wires and all new plugs. Mine starts but sounds like hell when it does get going. Fuel or fire are the obvious first things to look at. Spark plug gap should always be done since plugs settle from the shipping. I always use motorcraft plugs.

Now with that in mind, maybe look at the fuel delivery system. You may have a bad fuel pressure regulator, a clogged fuel filter or a bad fuel pump or simply a fuse that went out for fuel delivery. Just a thought. In addition, i would put the key in the ignition and try to listen for the fuel pump whinning. It is a low zzzzzzzt. Do not crank, just get close to cranking and when you power on the fuel pump should whine. You can hear it with the doors closed and quiet outside or in the garage. If not you might need to check out the fuse for the fuel delivery system. If not the fuse, then maybe the 12 v pump went out. I would definitely change the fuel filter if you havent already done so. Always a good practice. If you use seafoam, which i highly reccomend, then the octane and additives may have dislodged some tank trash and caused a clogged filter which wont let you start the vehicle.

If this is not your issue, sorry. It would then be a possible compression problem. This would also cause the motor not to start if bad enough. This could be a piston, ring, valve etc... I would think though, it isn't so. Usually a big give away when the rings or valves or pistons go.

The other possibility is you have a bad timing chain, timing issue or broken chain.

I am a good shadetree, and have had the timing issue do the same. No starting of the vehicle. I dont have a lot of valve, ring, piston troubleshooting experience, but am told a good possibility. I may have to do a complete rebuild on my 2000 4.2 v6.

Good luck and hope this helps you somehow.

geoffrey