Frozen Manifold Heat Control Valve

That is correct. It "slacks off" as the engine warms and allows the valve to open very easily against exhaust pressure.

Yep. And I wouldn't have know there was an anti rattle spring on the other side without having read about it in the reprinted Dodge Factory Service Manual I learned about on this site. Man, I've had this car for a month and that book is already dog eared and grease stained.