ECU geting very hot.

My ECU is getting very hot I can drive for a while but eventually get so hot that it shut the engie off I let it sit for a few minutes to cool it down it will start and run fine until it is hot again what could cause this? I am at my wits end tomorrow I am getting a new ECU from my friend and if it does the same thing I guess I'll start looking at electrical but I haven't touched any electrical.

it gets so hot you can't touch it and I have actually seen it smoke

edit: also thought it was worth mentioning that if I restart it right away it will start it will idle extremely low and it will only run on 3 cylinders I have tried unplugging and replugging every connector

I'm pretty sure theres water damage to my ECM

will it hurt to spray the ECM connectors with wire dry I use it on my spark plugs when they get wet but don't want to ruin it anymore