The car is an 84 300TD Turbo Euro. I'm the third owner and have had it for about 3 years. Odometer says around 190K, but it's slow, off by about 13% as checked with GPS, so the car might have closer to 200K+. It runs much, much better than when I first got it due to alot of work I've put into it, but it still has a smokey, rough idle that I haven't been able to get rid of. It also smokes at very low, constant speeds, other than that it runs great. The smokiness does not seem consistent either. It happens more often than not, but sometimes the idle seems just fine. Outside temperature doesn't seem to affect it. Normally it starts fine above, say, 25 degrees, but sometimes it stumbles a bit on the start. Again, not a consistent problem. It burns some oil, but it's not awful. Car runs at a consistent 80-85C.

What I've done that might aid in this discussion:
-air filter (this actually very recently and it made a huge difference in general running smokiness), fuel filters, diesel purge, fluids, belts, basics
-valve stem seals
-valves adjusted (again just yesterday, a couple tight ones, but nothing too bad)
-compression test (today, got 300-305psi on all cylinders in 8-10 cranks, not great, but not bad either)
-updated glow plug relay, new glow plugs, all tested and working fine
-cleaned glow plug holes of carbon with that special boring tool
-adjusted ALDA (I live in the Rockies at about 8,000ft - this was a must!)
-replaced leaky shutoff vacuum element on back of IP
-replaced all fuel lines (old ones were rusty and crumbling), checked fuel tank screen (it wasn't blocked with anything)

After much forum surfing, this is what I haven't done, but maybe should:
-I haven't ever removed or inspected the injectors/pre-chambers (I'm thinking I might do this next)
-have never messed with the injection pump (drip timing or rack damper or anything else besides the shutoff element)
-have not checked timing chain stretch or anything to do with timing (I think the chain is supposed to be changed around 200K so this might be an upcoming task)
-have not performed a leak down test
-still have the old fuel primer, but it doesn't appear to be leaking

So, my question is what should I do next to try and get to the bottom of this problem? It's kind of embarrassing when I'm at a stop light or idling somewhere and all of a sudden I'm surrounded by a big cloud of smoke. I'd really like to fix this issue, especially before the snow sets in...

Thanks in advance for your help and let me know if you need any more info.

Tripp

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'84 Euro 300TD Turbo, 192K