You are assuming that gridlock made those issues worse. I contend that many things would be worse if it weren't for gridlock. Take the debt ceiling for instance. A law was passed that established that any increases in the debt ceiling would be offset by budget cuts. The Republicans, some of them anyway, wanted Congress to uphold that law under the belief that we can't keep going the way we have been. They fought valiantly but enough of them eventually caved. Incidently, the increased debt is what caused the lower credit rating so you are helping to prove my point.
On polls, it isn't so much the number of people polled as it is their political tendencies and the likeliness that they will vote. A poll skewed with more people from either party is likely to have the opposite result from a poll skewed towards the opposite party. A poll of people not likely to vote isn't very meaningful at all.
I think Fox appears more skewed than they really are because the rest of the media is Sooo left but even I acknowledge that their right side is dominant. They do however do a better job of giving the left a voice in my opinion. Usually the debates are one-on-one where the other networks have a token right vs a panal of several left. By the way, Fox's ratings are way ahead of the others so whatever they are doing, the public seems to be reacting favorably. Of course, it may be more due to the fact that Fox gets 100% of us conservatives where the liberals have dozens of networks to choose from.
The "lowest opinion of Congress" might have more to do with what they did than what they didn't do. Dozens of bankrupt companies like Solyndra, open border policies, Fast and Furious, Executive Orders and Cabinet Appointments in the dead of the night without due process, no budget for three years even though our Constitution mandates that there be one, passing Obamacare even though the majority of the US does not want it, blocking the Canadian Oil Pipeline...I could go on-and-on. However, when you speak of the low opinion of Congress, you have to realize that is a two-edged sword that cuts both ways. You can't tell me that there isn't also some dissatisfaction coming from the radical left that aren't happy that Gitmo is still open, that we still have troops in Afganistan, that we still show minor support for Isreal, etc.
On a seperate note...Bloomberg is reporting today that 79% of General Motors sales last month were to the US Government. What they don't report is whether they were purchased at a fair price. The US Gov't is obviously not getting bids so why should they be discounted?
Anyway, keep this in mind when Obama/Biden tout their role in the GM "turnaround".