Idle air control valve ?

[Bru]

There is a test procedure in most repair manuals. It's a "stepping motor" so that means to get the valve plunger to move in one direction you have to activate the positive pins in a sequence. The reverse sequence moves the plunger in the opposite direction. After shutting off the engine you should hear a buzzing clicking sound that is indicative of a functioning idle control valve. You can disassemble and check for crud build up on the plunger and clean it. Be sure to get the check valve that goes into the intake manifold installed in the correct direction. The rubber diaphragm goes into the manifold body. Under turbo boost conditions it blocks air from backing out through the idle valve. If your hose is pinched it may not be a factory formed hose. It should have the same texture as the other hoses used on the intake bellows.