yea only coolant passages adjacent to cylinders are the end cylinders. so if you find coolant in the middle cylinders it's a crack.

anyway, since you now know you have a loose sleeve, and you know you are loosing coolant somewhere, and you are getting misfires on the center cylinders, and you think the center plug or plugs were steam cleaned, you probably have a crack.
BUT you need to know for sure.

So..pressure test to find the leak, look in the cylinders for steam cleaning or coolant.

 

Do the thermostat bypass, and dump 2 bottles of blue devil seal and go in there. Otherwise replace the engine. Only 2 ways to solve your problem.

 

Whatever came from your situation Sarge?

I've got the knock on the driver side of the engine, down low on the block, only when engine is cold and at idle rpms. I think I may have the slipped liner or cracked manifold. Just curious what you ended up finding.