I Know this thread is old but I guess ill post this here anyway.
Ive been having some weird problems similar to the ones described here. I replaces the IAC but I still have the same intermittent low idle. It never happens while driving and once it starts i can give it some gas and it stays running and usually goes back to idling normally. if i do nothing the RPMs will drop untill its almost dead then fire up to 1000 like i hit the gas. It will do this a couple times then completely die. Then it starts and idles just fine again.
My question is about BerryBros4X4s post. He said the computer only checks the map once when you cycle the key and then again every time you hit WOT. I don't know if this is normal but if i ever pull off the vaccum line to the MAP the engine dies immediately like turning off the key.
My timing is at 12', (i know its supposed to be 10 but it just seems to run better this way) It does change slightly, like plus or minus 2 degrees, while idling. I always assumed this was normal but Im so stumped with this problem that im starting to question things i though i knew.
Does anybody have links to testing procedures for all the sensors so i could test them with and ohm meter?