I have a 96 buick regal 120000 miles, 3.1 v6. I went through an intersection with high water, and a vehicle coming the other way pushed a lot of water over my hood. Car stalled immediately, when I got it home I pulled off the air intake, and the trap was completely full of water. I took it off and let it sit for a day, when dry I restarted the car and now there is a very loud knocking from the top end of the engine. I am quite mechanically inclined and can change or repair almost anything mechanical, I am just trying to find a starting point. If it may be something major like a piston problem or connecting rod I will probably have to take it in. Thanks for any help.
Did you check the oil to see if the crankcase has water in it? In the older carb days we used to introduce small amounts of water through the carb to break up carbon. It may be that the water has broken some carbon up and maybe hanging a valve open or something. Does the noise sound like a lifter?