Recently I got a tune and was seeing WOT spark retard above 3,800 rpm that wasn't there in the stock tune. I got the stock main & extended timing tables put back in and kept the other tweaks in the "tune" for the increased performance in DD'ing conditions. Spark retard is much more reasonable now but I'm still seeing some and STILL seeing 2-3* more timing advance over stock in Datamaster running the "tune". I checked using tuner cats and the "tune" does have the stock main & extended timing tables untouched. The 100% stock tune shows 35* total timing @ WOT above ~5,200 in Datamaster. Using the stock timing tables, the "tune" shows 37* total @ WOT above ~5,200 rpm. I want to get it back to stock 35* total WOT. After checking everything I physically could on the car and trying different gas stations I'm thinking this car just does not like the additional timing above 3,800 rpm.
Before I do anything, am I right to start adjusting the timing by using the main & extended timing tables in tuner cats in the correct rpm/KPa ranges?
1994 Z28 4l60e- B&M trans cooler, Yukon 3.42's, Tune, 160 stat, TB Bypass/Airfoil/1LE Elbow/K&N CAI, FlowMaster Cat-Back.
Suspension: Strano Springs & Sway Bars, Bilsteins, SFC's, LCARB, Founders Performance STB & Adj. PHB