So its pretty close to VT
I would guess you need to select some PIDs defined in the guide which you must be doing right, probably try and show MAF volts on your AP to watch while you go for a drive.
each cell is in incriments of 0.39v, I have been taking a tick sheet with me for maf cal, hold the car at a steady voltage point for a few seconds ie 1.2v, then go to next voltage and so on (when you review your log it should look like steps) the maf volt and throttle plate position should be parralle, the actual lambda and desired lambda should be the same, at that point your ltft% will be correct
Every man should have a V8 ute.....with a Chev badge.....and a Southern Cross sticker! Mods? What mods?