so i got my jeep from a guy who never changed the oil in it "that im aware of" but as of now it has 214,700 miles on it. I changed the oil last summer and the filter and untill now i only put 30 miles on it, i only went mudding with it in about 2 feet of water and today i changed it again and its very milky and smells like gas. i have no idea what it is and also while its at idle it makes a rattle noise and shakes pretty bad i even pulled of # 4 plug wire and the motor rpm never changed.
Sounds like you have a couple problems.
1. Was the oil milky before you went thru the water?
If so, sounds like either a bad head gasket, warped/ cracked head, or cracked block. If it wasnt milky before it could be that you sucked water into the motor which will take at least a couple oil changes to get it all out, or drop the pan and clean it.
2. If your oil smells like gas, its running to rich which will kill the rings and bearings.
3. What year is your jeep, tell us so we can give advice for rich mixture. It says 91? So its a 91 cherokee?
4. Sounds like a dead miss on cylinder 4, does cylinder 4 have spark?
5. Do a compression test, if the miss started after you sucked water in the motor it could be cyl. 4 has no compression because you bent a valve.
6. Report back with findings