[sik97s14]

hello everyone, see if you can help me out here. i was driving my 240 around town the other day and it had just finished raining. i went through a nice size puddle of water and my car stalled out. it has an injen cold air intake with just some headers and 3 inch exhaust with a magnaflow. i let it sit for about 10 min and started it up again it smoked from the exhaust so i gave it a couple of revs to clear out, and i noticed a knocking noise. knocking sounds like from the top end but not sure. checked all the exhaust and pulleys and everything seemed fine. took the valve cover off and couldnt see any real damage. timing chain is tight. i dont know if its a rod knock it isnt that loud. car revs up like normal and drives like normal, just knocks. no chocolate sludge in the oil. plugs looked great. car has 143k miles. any ideas? thanks and any help is greatly appreciated.
1997 Nissan 240sx