What would cause multiple cylinder misfire. I put new plugs and wires in. The light went off. I drove about 25 miles then it came back on. I drove about 100 miles now waters in the oil any sugestion?

What would cause multiple cylinder misfire. I put new plugs and wires in. The light went off. I drove about 25 miles then it came back on. I drove about 100 miles now waters in the oil any sugestion?
More than likely, you have a blown head gasket or a cracked cylinder head or cracked block if the oil and water are mixing together. The multiple misfires were probably being caused by the contamination.