I struck out there too. No data on the 1227148. I searched the gearhead forums a few days ago with no luck either. I'm working adding my own peak and hold injector drivers using the Cherry CS-453 drivers. I just wanted the schematic to double check my work, but I opened up the ECM last night, and GM was nice enough to label the collector, base, and emitter pins on the OEM drivers. I'm going to install the new drivers tonight. I expect all the go well, but we shall see, I have never done it before and there seems to be zero amounts of information out there. Would there be any interest in a write up on doing this? I'm not sure there is much call for this anymore, but I'll document my steps and post them up if I get any interest.