Looking for any help anyone can provide with an issue that I can't seem to get rid of.

Service visits:

May 16, 2012 - 55,228 mi (For misfire)
June 11, 2012 - 64,930 mi (For misfire)
Aug 06, 2012 - 66,202 mi (For misfire)

Needs service again for misfire now at 72,000

What they've done:

-Replaced all plugs
-Replaced 3 coil packs
-Replaced a single plug
-Reflash
-New left cat

Each time the symptoms go away but I feel like the underlying problem still exists that obviously is bringing the same issue back every other month or every month.

Before this was annoying but last night I nearly died passing a 18 wheeler when the truck fell flat on it's face with traffic coming.

Other than the misfire I love my truck