I can't seem to figure this one out. This is a 4.3 vortec swap to 5.7 vortec. Its a completely stock engine using a 2002 Express file from the repository onto a 0411 pcm. Every time I start it up, I get a P1665 which baffles me. According to Alldata, it deals with the fuel level sensor. Other places, it says its the because of the solenoid in the EVAP system. I compared schematics to both platforms and the PCM pin is in the same location on both the S10 and the Express and power is provided via the fuse box in the engine bay.
Here's the kicker. If I open up my stock V6 file, use the drop down menu to change it to v8, I don't get that error code anymore, but the engine runs like poo.
2002 Express schematic
expressevap.gif
2002 S10 schematic
s10evap.gif