95 ford Taurus idle problem?

I took it in had it checked they said it was the air idle control valve replaced it an it still likes to idle high sometimes an takes a couple try's to start an the servise engine soon light will come on but go off after 2-3 secondsbut always starts always runs great, what else could it be???? Took it back in after I replaced the valve an they said that's what it showing again???? Thanks for any help