There is no way that anyone envisioned Iowa's passing game to be as horrible as it was in 2016 before the season started. Two 1000 yard rushers. A good defense (for the most part). A decent set of special teams. Horrible, horrible passing game. Frankly, it's amazing that their running game was as sound as it was given that they were no threat through the air.
Regular season stats - In their 8 wins, 27% of their possessions were 3 and outs. In their 4 losses, 43.5% of their possessions were 3 and outs. This does not include drives that ended at half or at the end of the game. I think this is telling - I believe a passing threat would have changed that - given the defense more time to rest. It all feeds on itself.
Surprisingly, their 3rd down conversion rates were about the same for games they won and lost, around 35%, but there are a lot more touchdowns in the wins, so perhaps that neutralizes the 3rd down conversion rates in those games.