I have a 1997 base model F150 4.2L that just recently started misfiring on no#2 cylinder. What I've done so far changed plugs, wires, coil pack, misfire still there next changed the fuel filter and the injector still misfire next pulled the catalytic converter assembly and installed a test pipe and although the right bank was completely clogged ( I have never seen a coverter that clogged) still misfire. also tried seafoam and I did a full compression test and even a vaccuum test everything is within acceptable range still have the misfire. I'm running out of money and I am out of idea's please help me!

 

Had a similar issue to yours on cylinder 6 on my '97 4.2...pull plug #2 and look at it, check for a coolant type smell, also pull the dipstick and see if the oil is clean or um not. If it looks like bad whipped creamish stuff then suspect the following. The lower intake gaskets are known for blowing and allowing coolant into the oil and conversely, cylinders. Mine blew bad right near cylinder 2 so bad it took the engine with it.