looking for the reason making timing on idle negative specially with camshaft upgrade
LT4 with 2.31 making almost -5 to -10 timing on idle
L83 with cold air intake make -15 to -10 on idle
L83 with camshaft making -5 to -10 on idle
is thats symptom of air leak and PCM try to correct itself or needing work on torque management also there are shearing the actual RPM less the commanded RPM (happen on D and less on N)
WOT and cruising is perfect even not stalling but with 0 paddle
regards