I just bought a 94 Jeep Grand Cherokee. It has in the inline 6 with 204k miles on it. These are the things I'm troubleshooting: when it parked and idling, it smokes. The smoke is white and smells like oil, but when you drive it, there's nothing. I even followed behind someone while they were driving it to see if I saw any smoke, but there wasn't any. Other problem is, every once in awhile, it's misfiring. It rarely does it, but when it does happen all I have to do is turn the truck off and back on and it's fine again. I did a code search on it and the only code that came up was code 55. Thanks for the advice.

It look to me that your valve seals are leaking. It can be done without taking the head off, but it is difficult.