My '91 350 SDL will do this once in a while in very cold weather, only after having cold soaked over a long weeked (a few days). Burns no oil at all between 4000 mile changes and runs well otherwise (although I wish for about 50 more HP)

Agreeing with Old South ... I think the blue is just barely blue (on mine) ... looks more whitish/gray and sounds like an injector or fuel has pooled somewhere ...

I removed and cleaned the crossover and the intake manifold ... if you know the new design (assumption) rods were installed, take a look at the crossover and intake tract ... and, clean it ... you will likely be amazed at the gunk.

__________________
George Stephenson
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg