Bad ECU? need help!
 

Hey guys
this is my first time posting on this forum.
I have a 1990 Z N/A AT and recently ive been having bad luck with it.
im suspecting the ECU is bad.
here is what im experiencing.
1. Nothing electric in the car works except the radio and head lights. i.e no turn signals, no cruise control, nothing.
2. transmission only shifts when i shift manually. (it shifts fine when i do so)
3. The engine losing power. and misfiring at times. BUT not during IDLE.
4. No power steering. (not that im complaining about it ;))

I checked the red LED light in Mode 2 on ECU but it gave me the code 55. which says No Diagnostics Errors...
Also disconnected the battery for a good 30min to reset everything, but again, nothing.
i used to sometimes hear a flicker coming from the same area as the ECU.
Is my thought in the right place ?