I made another graph, similar to the one comparing the Ohio and Pennsylvania votes, comparing Pennsylvania and Indiana. The line is x=y, meaning that if a point falls on the line, Obama did exactly the same among the demographic group in Pennsylvania as he did two weeks later in Indiana.
As the graph shows, Obama did considerably better in the latter primary among almost all these demographic groups. In theory, the ones most likely to be receptive to Hillary Clinton's gas tax holiday were the low info voters and the poorer voters. Yet Obama substantially improved his stance among those with just a high school education and among those making less than $15K annually. He lost a little ground among the elderly and white Protestants, but not by much.