#1-- go over to the Taco section and get into the FSM sticky there; seem to me we have a 2003 FSM there. Look up the emissions components you mention to make sure you don't have some stupid semantics going on. <img src="/forums/images/graemlins/shame.gif" alt="" /> There's usually a component page for each subsystem's component locations. Be mindful of which engine type you're looking at however.

#2 Worth bookmarking; the tech articles there are extremely helpful--- www.autoshop101.com

I've never heard of the part you're talking about being changed, but then you're driving a pretty new rig; not something we see a lot of here. Other place to ask might be at www.ttora.com or www.tundrasolutions.com to see what might be trending, if anything.