I need an Idiot Guide to open and closed loop
 

what is open and closed loop... and what would happen if your car did not go to open loop at wot?
and last how would you fix a car that would not go into open loop at wot?

Not sure if it's what you're looking for, but it's a good explanation:

http://members.aol.com/InjuneerZZ/Sc....htm#step%2014

scroll about 1/2 way down the page where it begins talking about air/fuel management.

thanks, this helps...

I bet you're at WOT and looking at the scan data, and seeing the flag that indicates "closed loop enabled". That does not mean its in closed loop at WOT, only that the conditions required to operated in closed loop have been met. When you go WOT, GM does not call it "open loop". They call it "power enrichment mode". O2 sensors are ignored, just like in open loop, but they call it a different name.