You may have a worn throttle body. My truck did the same thing after I cleaned it out. I inspected it more closely and found the the throttle plate has slightly worn the throttle body on the side opposite the cable and springs. The little bit of gunk that was in there prevented it from leaking much, but cleaning it "solved" that problem, so now air leaks around the plate. If I wiggle/push on the throttle I can sometimes get the idle to drop back down, but its kind of hit and miss.

For this reason, I don't recommend cleaning these things. I've never seen one that was dirty enough to cause problems. Ironically, the problem starts after we clean it.

Solution is live with it, replace the TB, or have someone like LC Engineering bore it out larger, which is about $300, but its still cheaper than a new one.