replaced heads on 96 4.0, still runs bad

[mlclayton]

I know you guys have heard this one before (probably many times before), but I just replaced the heads on my buddies 96 4.0 ohv explorer, had a crack in between the valves in cyl. #3, and after changing both heads, putting new plugs, wires, coil pack, fuel pump, and testing everything as best as possible, it still has a miss. Some times it seems to run good, other it misses like crazy. I have no check engine light on as of yet after driving it around 60 or so miles. Has good vacuum, good fuel pressure, and spark at all six plugs. He bought it with the cracked head, and we don't have any real info on the past of this motor. The one problem we did have was after putting it back together, a water leak in the back from the intake gasket. We used a Cortico gasket set, a company I'm not familiar with, but I pulled the intake, replaced the gasket with one from Felpro, and no more leak. Does any one have any idea where I should go next? Any help would be greatly appreciated. Thank you all in advance. Mike

 

[Dono]

Hows the compression in the cylinders? Spark? How about injectors?

While the miss is happening, you can remove one plug wire, see if the miss gets worse, and plug the wire back in. Move to the next plug wire. Do the same thing. This should at least give you an idea which cylinder is missing.