This is really annoying on a high horsepower setup. Is there a fix to prevent the SA from dropping like it does? Example; Runs fine, lift throttle, still okay, then as the car is slowing down all of a sudden about 20 or more degrees are pulled out (no knock) and it starts to backfire through the exhaust as expected... I'm because my TunerCat file doesn't have anything that'll change this and I've even looked through some code and can't find this routine.

 

Idle spark advance pulling out trying to hit the commanded idle speed quickly???? I have no LT1 experience, just tossing out a guess. Maybe theres a way to limit the amount of retard allowed in that mode.

 

Well the $EE mask has a closed throttle SA vs RPM table, then there is a DFCO SA retard that takes out 15 degrees (stock) from that leaving you with single digits for SA and a bunch of backfiring on any "healthy" Lt1 bolt-on engine. So I'm assuming that is the case for the 93 ecm as well.
I'll do a compare and see if I can't find it in the $DA3 mask.
If I find it I'll let everybody know, even though there's probably like 1 person in the world that's interested in playing with these things.