Help! 2001 3.3 V6 naturally aspirated Xterra.. My lady was driving home and the engine started running on 4 or 5 cylinders and began smoking mainly from the heads and air intake. Prior to this issue, the oil light would stay on for 10-15 seconds after starting, I live in the mountains of Colorado so it has been cold. Now the truck is parked at home, I ran the code scanner and initially also got the P0030 code for the knock sensor. I did the bypass and relocated the sensor but nothing changed. The exhaust manifold on the passenger side is definitely cracked as well..The question I have is what causes the misfire? I know plugs wires distributor, but I'm not leaning that way with the symptoms. The distributor cap was replaced about two years ago but I haven't done the plugs or wires in the 5 years I've owned the vehicle. Any ideas? Thanks!