Can some tell me what all this means?
 

Recently got the following error codes on my 1991 C2. Can someone tell me what if anything I need to replace/repair? Thanks in advance.

http://forums.pelicanparts.com/uploa...1558831049.png
http://forums.pelicanparts.com/uploa...1558831049.png
http://forums.pelicanparts.com/uploa...1558831049.png

Nice tester....

First and foremost at a major service or CEL I unplug a coil and see if it runs, then the other. You can actually do this with the tester now, under drive links I think. I say this because of the knock fault. The heated O2 sensor fault can be tested with conventional diagnosis.

Clear all other codes and see what returns. Most are redundant faults due to low voltage...