So my 22R generally runs great. But I was on a trail the other day and saw smoke billowing from the back of the truck, presumably from the exhaust pipe. The smoke continued for 20 seconds or so, then stopped. I was on a medium incline, probably not the steepest of the day. As I was in a very expensive place to be towed out of, and since engine temp and oil light were fine, I just kept going and got home fine--truck ran great all the way home. See video for smoke; it looked mostly white, maybe bluish tinged, and smelled mostly like oil. I didn't pick up any burning coolant smell.
So far it doesn't appear there is any coolant in oil, there may be oil in coolant, I haven't really checked yet. Here's what the engine looks like:

My first thought of course was head gasket, but I'm not sure if that would be likely to cause such severe smoking and then go away like it never happened. My other thoughts are maybe a PCV valve problem, or a bad valve seal. Any other guesses or votes for what this might be?

 

Well just thought I'd follow up on my own post in case anyone else has the same symptom...many miles on the truck since this first happened, interestingly it has happened almost every time I've hit this trail, which goes from steep down to steep up when it crosses a ridge, and it has only happened on this trail, and it happens within the same 1/4 mile of trail. Not really worried about it since otherwise she mostly runs like a top. My best guess for what is happening is related to the LCE dual row timing chain upgrade, which requires modification of the baffle at the top of the valve cover near the timing chain. I think this mod allows some oil to collect on the top of the baffle when going steep downhill. Then headed uphill the oil flows into the PCV system, creating the smokescreen.

 

That is an interesting theory. Did you call LCE?