Is my 97 Tacoma computer bad?

I have a 97 Tacoma 4 cyl, automatic. Has very high miles, but was running very well until last week. First noticed the AC compressor not turning, and almost simultaneously the "check engine" light comes on. With that the engine idled OK but did not want to take gas to accelerate.(kind of like spark not advancing.

Had two different mechanics try to diagnose. When trying the OBD tool it came back with
"link error" even trying two different OBD's.

Next day the truck cranked and ran fine with no "check engine light" and the air worked fine. Mechanic checked again with OBD for residual codes and there were not any. Advise was to drive it until it happens again, then bring it back. OK the rest of that day.

Today it cranked OK but the "check engine " light comes on again, and has the same '' run bad"
symptoms, and once again, the AC compressor not turning.

Has anyone experienced these sypmtoms, if so, where should I look next?
Appreciate any suggestions. Jim

 

I'd just check for simple stuff first, like loose connection at the computer. There are three or four plugs back there and one of the management ones could be loose.