high idle sticking

Dr Dyno, i know i asked this already and feel free whoever else can help me. I have that problem of the idle sticking at 3000 at start up and it does it until the third time i start the engine. I start it, it sticks at about 3000 rpm and does not come down. What was it i had to do to solve this. It has bothered me for years and today i decided i have had enough. Also do u think this could have done any long term damage to the engine? Also, sometimes it idles a little high when driving causing the tranny to shift all wacky. Im going to do a bored throttle body and spacer next so should i do a 60 mm or 62 mm tb since my motor is all stock internally and will this have anything to do with solving the problem?

i had a similar prob w/ mine.
it was the tps (throttle position sensor).
buddy at the dc dealer told me untill i get it fixed to cycle the ign. 3 times and then start it. it worked.
the next day i had them changed it, cause the idle has to be adjusted through the obd.
hth
-g