A stalled motor/limp mode on my '08 Ford Focus (pre-facelift) 2.0 S. Help, anybody?

I have a 2008 pre-facelift Focus 2.0 Duratec HE.

It has been 3 times, I suffered a stall/limp mode on my focus, after driving in traffic jam (not in the traffic jam, the symptoms always came AFTER I've manage to brake loose from the traffic jam. The car works fine in the middle of the traffic). Oh, and NO CHECK ENGINE

And everytime I've check to the shop, the error code was always been the same, something about HO2 and AFR being too lean. My first tought was the hose from air box to the throttle body was loose (it was kinda loose) and the shop already fix this problem & reset the code from my car.
But it happened again. Same symptoms, limp/stall engine, rough idle, etc. But no solution at all…

The car was in such healthy condition, new oil, never late on service, tuned up, clean air filter, new oil filter, I even just bought new tires for it… Everything, except the error, was in great shape.

I was suspicious with the O2 sensors in my car, since I didn't get any decent fuel consumption, regardless what kinda gasoline that I put in, and what driving mode/style I used. I even try to use the tiptronic mode, to shift so I can ideal fuel efficiency. Nothing worked.
It's true right, when you have faulty O2 sensors, you got all the symptoms that I've mentioned above, PLUS bad gas millage?

Please, help me
This is my first Ford, and I love this car so much. I just want information about this problem, before I go back and forth to the shop again

Your overheating. That's why it only does it in traffic jams. There are many reasons that this might be happening. One could be a bad thermostat. One could be a bad head gasket. One could be the bottom radiator hose is collapsing and not circulating violent. If it's not any of those things, the only other thing would be a plugged cattalitic converter. Oh, one more thing might be s cracked head. Do you have ester in your oil? Do you have white smoke coming from your exhaust? With a violent type smell? A lot of things I know, but start narrowing down the list with the easiest first them go down the list. Good luck. I had a Cadillac with the same problem and it turned out yo be a BSD head gasket.