I just picked up a 1975 1/2 ton with a 250 inline 6 cyl, 1 barrel. There is a solonoid that pushed out the throttle when cold. When the engine warms up, the solonoid is suppose to release and drop the idle. Problem is, mine never shuts off. I can pull the wire off the back and it will drop the idle. I have no idea what controls this solonoid. I assume it would be a sensor screwed into the side of the block, but I'm not sure. Anyone know?? Thanks in advance. Eric M.