1996 f150 5.0l
When i first got the 305 code, i changed the plus and wires. Misfire went away for a little while. When it came back, i replaced the cap and rotor. It went away for a little while. When it came back, i replaced the coil and ran compression test. Also replaced the injector. All good for a little while. When it came back i took it to a shop.long story short a valve job turned into an engine overhaul. Now it's back and I'm going insane trying to figure it out. Please help before i lose my mind.

 

I'd start by looking at the pickup in the distributor. Make sure there's no corrosion, etc. I'd have the cats checked for blockage. If the O2 sensors haven't been replaced, now is a good time. If none of that fixes the issue, it's probably new computer time. They don't last forever and can drive you nutz with misfires and random codes. If you have an alarm on the truck, disconnect it as it can wreak havoc with the electricals too. I assume you used all Motorcraft parts. If not, after market stuff doesn't work well with the Ford engines including your 5.0. MY 91 Bronco 5.0 just has fits if I use anything but Motorcraft parts on it. If the PCV is not Motorcraft, it can also cause a misfire. Might check the firing order just to make sure. I had 2 wires crossed on mine and it would run fine but weak and then a misfire, then run clean again- go figure that one out.

 

I'd be looking at the distributor as a possibility. Also, 96 was the first year for a crankshaft position sensor (mounted on the timing case cover it sends a signal based on the position of that star shaped piece right behind your crankshaft pulley) - another possibility maybe.

 

If it were the CPS, wouldn't it throw a code? 96 is OBD2.

 

You would think so. But I take nothing for granted. Personally I take codes as a general direction map to get me looking in the right area. Not getting a code doesn't mean all is well, necessarily.