How do you remove the ECU to access the wires or terminals to clean them.

What is your question?

I removed the battery and the top cover of the ECU. I tried to pull off the plug unit but didn't want to force it. I need to get to the contact points and wires that exit the ECU. The former mechanic said that there was 12 volts entering the ECU but only 6-7 volts leaving it which caused my engine missing issues.