83 300SD rough idle when hot, done everything

[shadetree77]

hi all,

my 83 300SD still has the hot idle shakes. starts up right away even in 20F. idles smooth when cold. acceleration is awesome (one of the faster SD's what i have owned) here's what i've done (all of this needed to be done anyway, but i'm still bummed about the hot idle shakes)
-new motor mounts/ transmission mounts (all Lemfoerder OEM with the star ground off)
-new injectors (pop tested, etc.)
-new fuel lines (there are no visible air leaks in the clear lines from the secondary filter to the IP)
- cleaned tank, new fuel tank strainer
-new engine shocks
-new gold colored rack damper pin (played around with that for while and there's a definite slight change in engine sound when it hits the sweet spot)
- valve adjustment (about 5 of them in a month period; kept going tight but i think it was from the vehicle sitting for long, did italian tuneups inbetween


-chain stretch is about 2 degrees (checked via 2mm lift method), engine and IP has about 80,000 miles on it (rebuilt by reputable company{can't think of the name right now])
-messed around with idle speed but it shakes unless i go over 850 rpm (can't leave it that high since it will accelerate on its own going downhill)

Here's what i'm thinking (only ideas, would like feedback on these):

1. i'm guessing that the timing itself might be off; if i loosen the 3 bolts that hold the IP in and start rotating it will that affect the roughness of the idle?

2. the IP might be gummed up, would filling it with acetone (or something else?) help?

3. something went wrong during the rebuild (not likely, but i'll throw it out there)

ANY IDEAS WILL BE GREATLY APPRECIATED