Yeah, I'd try the throttle body cleaner and see if the engine speed/smoothness changes at all. Those pipes have been known to crack in places that you can't see unless you remove them.

I've been having the same problem, I too have just replaced my LIM/UIM and I get the same code. I have tried everything. I've been told that it may be the smog pump. We'll see what the dealer says, I'm done with it.

Apparently I in a rush to get my car back together, I never put my pcv valve back in the new plenum. I'm an Idiot. What a fine waste of $120 @ the dealer. I can't wait to have them laugh at me when I pick it up.

Hey it happens , atleast you know what it was and could have been worse.