As mentioned before it's been cleaned and lubed so it's definitely not sticking...

In addition I haven't put it back on since I cleaned the throttle body.



So anyway, I performed a test with the idle by-pass valve by putting a piece of tape over the port in the throttle body. Not to my suprise this affected my idle; I had to back out the Idle mixture screw (to where it used to be when all was well) and it idled just fine when it was warmed up.

I guess I'm going to fork out some dough for a replacement or find another throttle body assembly to test it with first. I'll keep this thread updated...