Idleing fast

This is my parents car. They took it to a local repairman, (for the second time) who did something to it which made it run better "For Now Again". What ever he thought it might be, he said it would cost "Alot" to fix . Do you Still think it may be the idle air control? and I'm sorry to ask, where might this part be located? Thank You Dave

Sounds vague! The idle air control valve is located at the intake manifold. Follow the rubber air tube from the air filter box to the engine. Where it meets the engine, that's where the cylindrical shaped idle air control valve is located.