I wonder if the crap is coming from the fuel distributor itself? I'd be more curious about solving the contamination problem before getting it running correctly. If it is too rich you can reset the mixture (test with on-off ratio or CO meter, on-off ratio being preferred). Are you sure it's rust, could it be rubber particles?
All I want to make sure is that I don't have a restriction upstream....if its just running rich I can tweak that.
I guess its probably time to put in my wideband o2 sensor in place of the OE Bosch unit so I can figure out whats going on.
In fact, it does actually look like rubber particles. Possible remnants from pump(s)/accum/fpr?
Maybe I can remove the fuel level gauge and peek into the tank and see if its okay or not.