The idle valve in your car is adjusted by the ECU by alternately grounding outer two pins while the center pin is provided battery. Varying the ratio of time between the open and close pin gives a range of valve opening. This happens at a fixed 100/sec rate accounting for that throb you feel in a properly operating idle valve.

A common trouble with LH2.0 and 2.2 idle valves occurs when someone mistakenly swaps the connector with the throttle switch, ruining one of the two transistors driving the idle valve. The symptom, I hear, is constant high idle. LH1.0 is a left coast thing -- only ever seen one, in a junkyard -- I don't know whether it is even possible to mix up these connectors on yours.

Getting around the price of the molded hoses is the interesting thought here. I often wondered if anyone has success taking stock straight hose and keeping it open through tight bends with a tape wrap. Just choosing the hose and tape sounds challenging beyond $35, but a look at how these silicone hoses are bent up seems to shed light on the process:



--
Art Benstein near Baltimore

What's the fastest liquid on earth? Milk, because it's pasteurized before you see it.