MMCD: ECU Comm Error

[Twilight Slide]

I saw a thread about this but it didn't really help so. . .
Car is a 91 GSX. Today it wouldn't start. After changing the spark plugs it will start, but only after cranking a while. Runs like garbage, and throws a cel. I tried to read the cell with MMCD, it gives the error in the title. Now I can log tps, o2v, rpm, etc. just fine,so what does that mean?
Thanks

 

[Rex2342]

Get the codes manually from ECU without using the logger. Go to http://www.vfaq.com/index-main.html and click on the electrical section then scroll down to learn to retrieve the codes. Also remember to disconnect the logger from the OBD port while doing this and let us know your results.