1998 4.6l v8 with p0303 code. Changed all plugs and installed a complete set of plug wires. Also checked fuel injectors, all are ok. Engine is still missing. This engine has two coil packs that run 4 plugs each. If a coil pack is bad, wouldn't all four cylinders that are controlled by this coil pack be misfiring? Any other ideas?

 

I had the same scenario last week. I figured I would have a misfire on more then one cylinder if the coil pack is bad...not so in my case. I checked the resistance of my coil pack, and the wires. Both were within there operating range. I kept getting a P0304 code which is cylinder #4 misfire. I put new wires and plugs on my truck and the problem went away for about 50 miles, then same thing problem misfire detected. I ended up putting a new coil pack on and so far (300miles) I havent had a problem. Make sure to use dialectric grease on coil pack and spark plug boots.