hello laughsofgreed, please try this: enter about:config into the firefox location bar (confirm the info message in case it shows up) & search for custom preferences (=shown in bold) starting with network.http... - right-click and reset those entries to the default value.

Thanks for the reply. I've done that and will see how it goes for a couple of days!

I've got this! I had this problem for a long time, tried changing the spdy preference, but it didn't help.

I think that the true source of the problem is Adblock addon! Once I disabled this addon, everything works fine.

I am not trying a conspiracy freak, but I suspect that Google did some clever trick to intentionally make life difficult for the Adblock users. I don't even know if this is possible, but if it were possible they should be doing it right now.