The carbon build up acted like sand paper and shaved away a small amount of aluminum, so when you cleaned the throttle body there is now to much clearance. This is very rare, but possible. I thought you said it got worse after you cleaned it. Have you disconnected your battery for a few minutes...
I have seen this happen a few times after the throttle body was cleaned. The carbon that was cleaned around the throttle plate left a gap between housing and plate, basically throttle body is no good. If you haven't diconnected your battery to reset the ecm memory after cleaning the throttle...
