[V8] Hot/No Start, running too Rich

[bw at UDel.Edu]

Tom, your Hot/No Start story has nightmare potential....
 Could we look at this problem beyond the sensors? One of my cars is currently 
plagued and the two ref sensors are new. The upper two of the three temp sensors 
are new. The distributors have been cleaned up. I know it is running very rich. 
Before it fails when hot, I notice it will backfire when the throttle is suddenly 
floored. The timing(?)/firing seems off. Can the cold start circuit be on when it is 
actually fully hot?
  Can anyone with an understanding of the mysteries of the engine management 
systems explain these symptoms that may be a secondary No Start problem?  Bob