I'm still chasing this issue. Not too long ago I changed out the whole distributor, which included yet another new ignition module when I thought the ignition module was to blame and I broke a connector in the distributor. A couple days ago when I was driving the truck, I got the code 42 YET AGAIN. At this point considering I'm on my 3rd or 4th module, I'm going to say it's not the ignition module. So, next down the line of possible offenders include the wiring and ????. Despite the fact that the knock sensor is part of the Electronic Spark Control (ESC) and not the ignition module, could I maybe have knock sensor issues that are causing the light? Could an ignition coil cause it? At this point I'm just throwing darts at the dartboard. Typically I'm a man of troubleshoot the issue and fix what's broken, but I'm pretty much flying blind here...

One thing to note is when I re-timed the distributor, I didn't go back to 0* like the label on the radiator core support said to do. I went to 3* BTDC. Despite the timing being presumably right on before the distributor replacement, could bumping the timing have caused or added to my woe? I also haven't pulled the plugs yet and should probably plan to. They can't have more than 15K on them, but they might give some additional insight to the situation.