I have read where some of you have cleaned your fuel injectors. I presume this is a recommended PM for 100k plus truck? How involved is this for a do-it-yourselfer? I have done everyting else myself, mods, birfs, etc., but have yet to do "get into" the engine. My local Firestone (trustworthy guys in my experience) are offering the following service for $50: *fuel system and injector cleaning *remove intake valve & combustion chamber deposits Is this something I can trust them with or better off doing it myself? Thanks for you thoughts.