Can you downgrade an iPhone that is not jailbroken?

I have an iPhone 4, on ios 6.1.3, I want to downgrade it to 5.1.1 because I want to jailbreak it, iTunes keepts doing error 3194 or something and I've done everything to try and fix it but it won't work when I try and downgrade it on that. Is there anyway I can downgrade it to 5.1.1 without iTunes?

No there isn't. I tried doing the same thing last year. I want iOS 5 back badly.
Apple stops signing iOS packages after they come out with a new iOS.
And that means, that they're pretty much useless.

What I recommend is, DO NOT UPGRADE ANYMORE!
evasi0n.com has the latest jailbreak software, WAIT will the Evasi0n team comes out with the iOS 6.1.3 jailbreak software and them jailbreak. Right now they're working on it.

And the Evasi0n software is the easiest to use yet. In my opinion.

A friend of mine has exact the same problem and the idea is factory reset it!
or, look at this link instead!
Where did I get it?
At the magical mystery tour of Google of course
glad i could help!
http://www.iclarified.com/25260/how-to-downgrade-your-ipod-touch-4g-from-ios-6x-to-ios-5x-windows

Yes there's. You need to find the firmware you want. Download it. Put phone in DFU mode connect to iTunes. A message will come up saying iTunes has detected a phone. Click ok. Press either left arrow or the shift key (can't remember which it was) another box will come up with with firmware you downloaded. Click ok or yes. And then leave it to soothe rest.
That's how I did it anyway.