Ford Repair: lost, spark plug wires, vacum leaks

Question
I have a 1993 E 150 ford van with 351 engine aprox 99,000 miles on it It has a slight miss at idle, Things that have been done so far There is no check engine light. When van was put on scope there was some peaking . Spark plug wires were changed and that solved the peaking. Plugs,rotor.cap,pvc,air filters, fuel filter,were. no vacum leaks, checked resistance at injectors also checked for bad diodes in alternater, Checked for bad grounds also checked compression and harmonic bal.maybe you can shed some lighton this

Answer
A slight miss at idle? Is it a definite miss, or rough idle? The 5.8 had problems in the throttle body gasket and the plenum gasket leaking.

You might have to go as far as pulling valve covers to make sure all the valves are operating as designed. A worn cam or stuck lifter, anything that affects valve timing or opening duration. Have you put a vacuum gauge on it? Many times this can tell you more than a compression test.