Harris Poll 2012:
“Almost nine in ten Americans say that political action committees or PACs (88%) and big companies (86%) have too much power and influence in Washington, D.C. More than four in five U.S. adults believe political lobbyists (85%), and banks and financial institutions (81%) carry too much influence inside the Beltway while almost three-quarters believe the news media (73%) has too much power. These are some of the results of The Harris Poll of 1,016 adults surveyed by telephone between April 10 and 17, 2012 by Harris Interactive.”
Source: “PACs, Big Companies, Lobbyists, and Banks and Financial Institutions Seen by Strong Majorities as Having Too Much Power and Influence in DC,” May 29, 2012, accessed September 30, 2014, http://www.harrisinteractive.com/NewsRoom/HarrisPolls/tabid/447/mid/1508....
Gallup Poll 2013:
In a January 7-10, 2013 survey conducted by Gallup, 51% of republicans, 62% of independents, and 70% of democrats said they are “very/somewhat dissatisfied with the size and influence of major corporations.”
Source: “Americans Similarly Dissatisfied with Corporations, Gov't,” Gallup, Inc., last modified January 17, 2013, accessed July 3, 2014, http://www.gallup.com/poll/159875/americans-similarly-dissatisfied-corpo....
[From quick search, corporations mainly donate money to political through PACs although this is not the only way in which they have influence and PACs are not the only means of campaign money, but according to https://www.opensecrets.org/resources/dollarocracy/04.php candidates get 90% of their money from business PACs
Also, the different poll results may come from the wording of the questions. One specifically asks about PACs and big companies power and the other (Gallup) asks about their satisfaction/disatisfaction of size and influence of major corporations. Semantics are everything...]