hey i have a b3000 that misfires. only 70k

its reliable and has steady rpms. ive been to several mechanics and here is the list of things weve done.
comperssion test all 6 between 150 160
new fuel filter
tps is good
new iac
new engine coolant temp sensor
new plugs and wires
got a motovac done
ran laquer thinner through it
tested for vacuum leaks
got fuel pressure tested
checked pvc valve
was hooked up to a machine everything seemed good.

we cant diagnose it to 1 cylinder sometimes its worse then other times
you can always feel the vibrate better if your reving it let of the gas and hits a 1000 rpms,

the only thing we havent done is a leak down test but ive already thrown so much money at it and dont know if this woud change it.
and i havent replaced the coil.( checked coilpack at the secondary their is 10.4 ohms between all of them, but cant get a primary reading ) but i figured if it was the coil it wouldnt be random cylinders

like i said we dont get any codes and everything checks out.this is driving me insane if anyone can help me it would be greatly appreciated

thanks