Possible ignition switch?
 

Hey guys, first of all I want to say this is an awesome forum I have already found a ton of useful information.

I bought a 96 Blazer 4WD 4.3L a couple of weeks ago. When I bought it, the shift selector light was off and it was running in limp mode (starting in 3rd gear). I had the codes scanned at Autozone and it came up with p1860, p1864, p0753, p0758. I replaced the TRANS fuse and the light came on, and came out of limp mode. But now it shifts a little rough between 1st and 2nd, and sometimes from 2nd to 3rd but not as often or rough. From what I have been reading here and elsewhere it seems that it might be an electrical issue and possibly the ignition switch. Would I be right in thinking this, or do I have another problem?