Hello - 2005 - 130K - Changed plugs prior but not the Wires/coil. Was getting some rough motor on hard inclines/hills at highway speed. Had a diagnostic check at a garage and misfiring - need tune up. Odd after the diag no symptoms for a month. Symptoms returned - went to autozone - 2 cylinders misfiring based on diagnostic. Bought 6 plugs and wires. Again symptoms seems to disappear but went forward and replaced the plugs and wired. The wires had a tough time snapping on with the grease the store provided (duralast wires). Started van - rough idle - tried running at 3k rpm - and it would drop - sounded sputtery at idle. Thought to got to local car part store for diagnostic and found it indriveable. Fealt like it wanted to go in gear at neutral and brakes pedal feel seemed odd too. WTH did I do?

 

You may hve misinterpret the code. It says misfire. It does not say what causes the misfire.
On the electrical side there is still the coil pack that could be faulty.
Then there is a whole bunch of possible causes for misfire:
http://www.oreillyauto.com/site/app/...icle=800649141

 

if you have'nt changed the coil pack, it is a likely cause.

 

 

"COPs"...That's weird. I've seen a lot of 4.2's but never seen a 4.2 V6 with COPs, they've always have been Ignition coil w/plug wires all the way thru the 4.2's last day in 2008. Could you post a picture? I'd really like to see that.