hey just wanted to pass along something that i have read in a book how to tune and modify chevy efi and here it is. It is stated within an article regarding diagnostics regarding tpi's that there is a service mode while the car is running. the article proceeds with jumping the adl a and b and the computer will flash at certain sequences or times and pretty much give you a running lean, rich, or ok. i was led to believe that when getting or running the diagnostic mode for codes or even minimum air adjustments the jumpers were removed before starting the car because of damaging the ecm. thanks tim( 1988 Iroc-z 5.7l)

 

That is my understanding, remove jumper before starting.