Multiple misfire error message
 

My 04 MPV has repeatedly given my the error misfire 1 and 4 over the past 2 years. I had replaced the coil packs and the plugs more than once with temporary success. When I take off the intake to get at the 4-6 plugs I saw that it was all varnished on the 1 and 4 end. (not exactly sure what that means but can't be good.) Seamed like the problem was worse during moist weather but is constant now. I had tried premium gas in the past with moderate success but is no help now. I'm going to tear it down again tomorrow and would appreciate any insight anyone has. I will replace the plugs again and check the gap. I'm also going to tear apart the wiring harness to see if I can find a short (maybe why it worse in moist weather) Thanks in advance.

Sounds like it could be the high tension wiring between coil packs and plugs.
Depending on length, the resistance should be in the 2000 to 6000 ohm range, and the jacketing should be free from nicks or cracks.
Likewise, check the condition of the spreaders and insulating posts to ensure the wiring is spaced off any metal nearby. A full OEM harness will cost about $50 and will include all of the insulator posts etc.
I did a writeup for Adam S some months ago, you can search that for a full treatment of your coil packs and harnesses if you like.