Hi,

Anyone willing to view my Tunerpro RT datalog and help me isolate the parameter(s) that might be affecting my park/neutral idle speed?

I have a 1988 Chevy R20 with 454 (7.4l).
TH400 3-speed auto tranny
ECM is 1227747 with AFTK chip originally
I have 27SF512 chip with Moates' switching adapter.
Engine is bare-bone stock

Problem: It idles at 900-1000 rpm in park or neutral. It seems to be fine (750-800) when in gear.

Things checked/done:
Replaced MAP, IAC, CTS, O2, intake manifold gaskets, throttle body gaskets, vacuum lines
Backprobed TPS and voltages were good
Performed IAC reset and baseline idle (throttle plate adjustment)
Timing is at 4 degrees BTDC at warm idle with ESC wire disconnected
Spent hours looking for vacuum leaks with various volatile aerosols
Replaced one fuel injector just to compare spray patterns.
Compared idle between 2 fuel pumps (I have dual tanks, each with their own pump)

What I have NOT done:
Not checked fuel pressure, but the spray patterns seem fine.

Other details:
Seems to have enough power.
I will attach a datalog
I noticed in the datalog recorded by Tunerpro RT that there is no spark advance but I clearly see a good bit of advance with my timing light when the ESC wire is disconnected, then back to 4 degrees BTDC when ESC wire is connected