#1 - knock sensor is not read by ECU below 3000 rpm+under load
#2 - the knock sensor code will get thrown if there is a problem in the knock sensor circuit, like a bad sensor or open wire...the ecu WILL NOT throw a code for the knock sensor detecting knock.
#3 - you have to jump your 'blue colored' service connector and then start the engine so the ecu is running in back-up mode when manually adjusting dissy timing, otherwise the ecu will remain in control of the timing and you wont get an accurate reading with the gun.
~kris