First of all, I am aware that a lot of 05 Colorados are known to have idling problems, usually because a dirty throttle body, or vacuum leak. I have been fiddling around all day, changed the plugs, bought a new Ignition Control Module (one of them broke), but the problem is still there. After I changed all the plugs, the idle got better, but not like it used to be.
I was looking around the engine again after I thought I was done, and noticed this... This big silver metal plate thing is cracked right around one of the bolts that hold it in place. (Pictures below)
My question is this:
1) What is this piece called, and is it easy to change? I am not a car expert by any means, but I am handy and can figure out most anything.
2) Could this be what is causing my low/rough idle because of a vacuum leak around this bolt?, or is it more likely a dirty throttle body?
Sorry, I couldn't anything specific to this in the search.