Originally Posted by TwinTurboGTR

Very good Drew,
Do not start chasing the problem because it won't solve anything. There are a lot of people on here; and I have done it myself, told the forum here, left and said "Damn, now I'm chasing a damn problem by throwing parts at it!"

Anyways, as far as the rough idle, it sounds like it has to do with the X breathing or emmissions. I would check to see the throttle body and look at that butterfly plate. If it is covered in carbon, that plate may have a hard time properly opening and closing. Carbon may be covering the plate, blocking air flow when the motor is in idle. If it is covered, hit it with throttle cleaner. I've done it on my X 4 times and no problems. You might trigger a CEL but it goes away after a few hours of driving. And emission wise, check the ERG valve a check to see if the valve is sticking, de to carbon build up. Anyone want to concur?

At least these things don't cost any money, well besides the $6 on the cleaner, and $9 for a 6 pack of bud???