OBD1 PCM interchange/compatibility, 5.2 vs 5.9

The original IAC motor didn't work at all, wouldn't idle. I replaced the IAC, mostly idles like it's supposed to, but it has been having random surges. I assumed it's because the PCM sometimes has to "retrain" itself after an IAC change, but it certainly could be a fuel issue. The truck doesn't die, which is what I've experienced previously after changing them. I need to put the gauge back on and run the motor a bit more, and I'll try it with the vacuum line removed. Lots left to stumble my way through, including taking some hella-better notes.