MAP or IAC sensor?

i really need help here my cars rpms are surging between 750 and 1200 when i drive at 35 km/h or less until i come to a complete stop or press the gas, this only happens when the engine stars to warm up and happens all the time after that. also when i shift to neutral(auto trans) the rpms hang around 2000 for a few seconds and then go back down. i dont know if this helps but when i start the car the rpms shoot up to 2000 and then slowly come bask down to 900. its a 93 sunbird gt 3.1. another thing is the check engine light only comes on after its been ideling for a while . i just dont have enough money for trial and error .... so what ive learned so far is that its most likely the map but because the rpms go so high on start up im also thinking its the iac ... this problem is anoying as hell so help me please

it could also be a vacuum leak.

yah ive been thinking that but there doesnt seem to be one

1st, pull the codes that the CEL is indicating are present and post them here. That will eliminate a whole lot of guessing.

Before you pull the codes im going to guess it is the Map sensor because when i had a little bit of an electrical fire thats what mine was doing when my Map sensor was bad(cooked)

Before you pull the codes im going to guess it is the Map sensor because when i had a little bit of an electrical fire thats what mine was doing when my Map sensor was bad(cooked)
Possibly he didn't have a fire and needs to diagnose what is actually wrong?

yah i dont have anything to check the codes so i guess ill have to get it done at the shop .... and one know if theres anywhere that'll do it for free in canada

turns out that both the MAP and IAC are gone i pulled the codes and got a 33(MAP) and 35(IAC) .... heres the how to i found on how to pull the codes using a paper clip http://www.v6z24.com/howto/codes its a great site with lost of how to's and a really good forum