My truck was stolen and now I have all kinds of issues. I am getting five codes out of it right now 1693-0463-0122-0545-1594.

Symptoms:

1. Intermittent Check Engine Light
2. Between 37 and 45 mph tranny is searching for where to be
3. Fuel gauge intermittently falls flat and then comes right back. No issue with this when tank is above 3/4 full
4. I have had to remove the horn relay because the horn will just go off with no rhyme or reason and stay blowing until I remove the relay again.

I am sure the obvious conclusion is something is grounding out causing all the codes and issues. What I am curious is if any of the experts here could point me to a central location (harness or ground source) that could be affecting all these things together where I might start tracing back from there?