Automotive Forums

I just got this 92 GMC Sonoma its a 2.5 fuel injected and it has been idling high every since I have had it. I cant find any vacuum leaks and i changed the oil, replaced the air filter, installed a new mufflfer and fixed a hole in the exhaust.
and it still idles high. usually if its been sitting for a while and i start it up and let it run for a while, then when i try to take it out of park and put it in gear, it starts idling real high then once i get it into drive and take off, it usualy isnt bad but sometimes even after I been driving all day and come to a stop and let off the brake, it will idle high and start moving forward.  Im not all that smart when it comes to vehicles so any help is greatly appreciated thanks very much