I have a problem with Firefox/Fennec on N9 (PR1.3), version is latest 14.0:
if I type some word on the bar then I use the 'Search with Google' applet, all I get is a "Error 502" from Google, at any time, with any connection, searching any word.
The interesting thing is that if instead from fennec I open a google main page and from there I do the search, everything works fine.
Also any other network access from the device is looking ok.
With F 12.0 the applet worked ok. I don't remember if I ran any successful search with F 14.0, but on the other side, a friends' N950 with F14.0 is fine.

Any idea where to look for to track the issue?

http://www.checkupdown.com/status/E502.html

Error 502 is bad gateway. I'd check to see if you have a proxy going in your Firefox settings, or some other odd configuration.

You may also want to dig around in "about:config" or maybe even rename your ~/.mozilla directory and see if that fixes it.

In terminal;
You'll want to do this while Firefox is closed.

I have exactly same problem with Firefox 14 Beta and now with Firefox 14 running Phony extension.

Google search works with default user Agent but not with desktop Firefox, Android (phone and tablet) or iPhone/iPad.

So I use Yahoo instead.....

Thanks to both.
Indeed, if I start my configuration fresh with
things work again, but if I then install Phony addon and I change the User Agent to something other than default, I get the '502 error' again.

I'll try to use set a private proxy to sniff all network traffic and see what's happening, and hopefully report something useful here.