2002 Ford Taurus heads

Engine Performance problem
2002 Ford Taurus 6 cyl Automatic 149000 miles

ok lets start from the beginning, my car began to overheat due to a crack in the water container. Thus leading to no water circulating the engine. I kind of just blew off the problem and it got worse. My car was having a hard time accelerating and was making a ous clacking noise. I change the water container and the roblem went away.

After a while the car wouldn't overheat, but all of the water from the container would steam out. I thought it was the container cap, so I bought a new cap and the problem was still the same. I was driving on the freeway and I was going about 80 miles an hour and the car was beginning to shut off. The loud clacking sound came back, but the water temperature was not very high. I pulled into a gas station and took off the cap to the water container and all the water rushed out at a high temperature.
I replaced the water and at first when I started the car it had a really rough shaking and then it was smooth. Then I shut car off and it began to steam out again.

I thought it was the thermostat so I changed ot. And the problem persist.I then started it up and rev the engine and the engine power was very weak. I checked the spark plugs and the gap was at like one thousandths. While replacing the spark plugs 4 and 6 were wet.

now my question is. Are my heads cracked. Or do I just need to change some gaskets. What do I need to do. Any help will be great.

p.S sorry for the length