powertrain vibration

[mborutski]

Hope some one can give me back my sanity.
heres the run down

94 3.8L sable wagon
SEVERE powertrain vibration at idle, in/out of gear moving or not.
checked spark, fuel, injectors, compression by cylinder balance test, gas analyser reads HC 28ppm at idle when vibration is worst. lots of power. checked harmonic balancer, ring gear weight and engine mounts. removed serp belt to check acceseries, ok. im going crazy!

six techs on this one and drawing a blank- engine silent, just bad vibes, shakes seats dash and doors. smooths out but still present up to 100k

S.O.S
MB