2004 tribute engine miss
 

Have 2004 tribute 3.0 v-6. OBD-2 says misfire detected first 1000 revs, random/multiple misfires detected, #1 and #4 misfire (last week #2 and #3 were also showing misfires). Have replaced coilpacks on all affected cylinders,have also replaced plugs and upper and lower intake gaskets. Should I be looking at a cracked intake ? Anyone have any insite?
Thanks for the help.

I had the misfire detected first 1000 revs, and random misfires detected only mine was all on the same bank(cyl 4, 5, and 6) and it turned out to be a bad catalytic converter on that side was clogged.