3.1 code p1381 p0300 lack of performance

[jtls66]

Symptom: My car lacks strong acceleration. Starts and Idles fine. No check engine light. I scanned my car and got DTC P1381
Misfire Detected - No Communication with Brake Control Module and also p0300 random misfire detected. I see the misfire counts are high for cylinders 1, 2, and 4. I checked fuel pressure and it was fine. I changed the module and coil packs to a known good unit from a good car and made no difference. Replacing the plugs and wires also made no change. Car has trouble getting to highway speed. Feels like cylinders are cutting in and out. I don't suspect a bad injector because the car would be rough at idle missing 1 cylinder. Also the car would accelerate pretty well short 1 cylinder. Anyone know what the P1381 code means? Thanks