When I took it off though I was surprised to see that the solenoid worked the way it does. I appears that it is energized when the butterfly opens and when your off the gas, (idle) the little spring opens the valve to let air past the throttle body. It seems to me that it should be the other way around. Mine was so gummed up that the valve wasnt even moving. After freeing it up and douching it out, I put it back on took it for a ride. Guess what.....no more idling problem.

If Im not mistaken...solenoids are rated for continuous duty or not. Since you spend more time on the gas than at idle, it would be energized way longer than not...and this is not a real good practice. It does make sense about the highway thing. When the solenoid is energized for a long period of time, when you get off the gas...the spring has to overcome the stiction in the valve. Making it harder for any air to make it into the intake. Any junk on the valve will make it that much harder.

Does any of this make sense???