You are right the pump can "sort of fail". A fin or 2 or more can break down and not move the normal volume of coolant. This is more uncommon though compared to the usual catastrophic failure most of us have had. As for your list it sounds like you are well on your way to solving the problem yourself. Rob aka SVTCANUK is the wiring expert. He may be able to assist you better with your questions.
As for the Emmisions. My vehicle is plated and that is all that counts right now despite the whole curb incident outlined in my "I pulled a Keioth post." I am still running rich and have some work ahead to solving that problem. Asap.
