help!!!!!!

Okay bone stock 90 da
I have codes 10, 12 and 43,

I notice the o2 sensor wring is all fucked up but I can’t find the original plugs for it. Can some one guide me where I could find the stock o2 sensor wires please? This is all obd0
The spark plugs are dark ass fuck!!(ima get new ones tomorrow)

The car runs fine I just get 23.3 mpg and I’m getting really irritated.
And just did the head gasket I have only driving It for about 150 miles so its fressssh

On and I have to be having the ac on in order for the fans to be on.
I tried looking for the oem wring and its missing I can’t figure it out

Last owner made this car a living nightmare

Can anyone give some tips and help me get rid of this problem thanks!!

http://forums.g2ic.com/announcement.php?f=29

USE APPROPRIATE SUBJECTS
Your subject should be a broad description of what your problem/question/topic is. For example, don’t post a thread with just “HELP” or “QUICK QUESTION” in the subject. Doing this will be regarded as pure laziness and the thread will be promptly deleted. Using appropriate subjects helps the search engine function better!. Also, do NOT use a different subject than what your thread is about, just to get attention. It will also be deleted.