This is very interesting to me in that when I first considered the "project car" 190E it was running VERY poorly.
A mechanic friend recommended bleeding the injection lines at the FD, something that I had never had hear of doing before. He was right, I bled each several times until all the vile, disgusting stuff stopped coming out. The car ran quite well after that.
I then learned of the "double-dose" of Techron: Two bottles of fuel injector cleaner in less than a full tank of fuel. I ran the engine up and down in RPM for several minutes. I then heard a very weird muffled "thwup" kind of sound and since the engine purrs. Incredible.
OK, long-shot: Maybe using a very intensified dose of injection cleaner in the fuel with some way to allow the fuel to mix and circulate could dissolve the crude in the FD. Or at least enough to allow the lines at the FD to be bled.
I know, itís a long short but costs a lot less than a new FD.
Keep us posted,
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)