96 MC knocking and will not start!!!

I have a 96 3.1L. I went to go wash my engine off the other night and when I started the engine back up it made a few knocking noises so I shut the engine off and then turned it back on and it seemed fine. I drove it home no problem. Well when I went out the next morning to go to work the car would not start. It was turning over but also making a loud knocking noise, so I tried again and it wouldnt turn over. I checked the fluids and everything was fine. So we thought it was the starter, replaced it and it turns over better and sounds like it wants to start but it still has this loud knocking sound coming from near the spark plug area. Any ideas?

possibly a bad plug. Check them, check if the connections on them are all good, coil and into the block, make sure the plugs are not loost when you take the boots off too. If you get water in there and they arn't tight.... not good.

Id deff check all the plugs. Takes about an hr if you have the time. I just spent about an hr changing the plugs and wires on one of my freinds 3.1 1997 lumina. Itd be best if you had the engine puller (not a cherry picker), by engine puller i mean the joints you put on the motor mounts and pull the enigne forward so you can get to the back plugs easier, but I did it w/out the motor mounts puller.

Good Luck