Michigan and Iowa have met 54 times, going back to 1900.
In only three seasons have the Hawkeyes been ranked and Wolverines unranked:
1954 #4 Iowa went down to 14-13 defeat in A2
1958 #2 Iowa won 37-14 in A2
1984 #18 Iowa won 26-0 at home
The last game is the only one of which I have any first-hand familiarity. A scrappy Michigan struggled offensively in its first road test after losing Soph QB Jim Harbaugh. The shutout was the last one for Michigan, whose streak of non-shutout games is an NCAA record.
Bottom line, not much history to go by, but if Michigan can keep it close, they might steal a victory. Go Blue!