P1381C code, what did I do??

I have a 1999 Monte, 3.1L, I changed plugs and wires and the next day my light came on, computer reads a "P1381C Misfire Detected-No EBTCM/PCM Serial Data" code. If I clear the code out it might go away for a day or two and run great, and then all of a sudden the engine starts missing and within a few seconds the light comes back on.

What does this code mean? Do I have a brake control module going bad, loose wire somewhere, what should I look for? This just happened after changing plugs and wires, did I knock a cable loose somewhere that I can't find??? Any help is greatly appreciated on this.

Did you gap the plugs? Routed the plug wires in the factory harness'?

Did you gap the plugs? Routed the plug wires in the factory harness'?

I did gap the plugs and route the wires the same as they came out. I have tried putting the old plugs and wires back on the cylinders that are missing with no luck. I have one cylinder missing on each coil pack, so I don't think I have a coil pack going bad. What else can I look for?

One dead cylinder on each coil pack? Thats strange.. Sounds more like a coil or ignition module failure. You can break the resistor by improperly gapping plugs