My MLT query uses a fieldlist of about 5 or 6 fields. There are a mix of string and text fields. They are all in a TermVector. I have played around with the mindf values. With about 90% of my mlt queries solr it returns no matches and the remaining 10% get completely irrelevant results.
Set debugQuery on to see the generated query. Also try mlt.mintf=1 if your source fields are singleton-types.
