Just had the same code like 3 weeks ago. You will need to replace the o2 sensor, and do yourself a favour and replace with a dealer one.
I had to use a torch to heat the manifold over and over whenever the o2 sensor started getting tight as I backed it out. Took me about 30 mins from start to finish although it felt like 30 hrs (engine was hot, i was frustrated, etc). Some people will tell you just stick some pb blaster to her and wa la quick wrenching and you're done, but I wouldnt expect it
2009 Ford Escape Limited - 3.0L, 6 speed auto, 4x4, 25/33 city/hwy imp mpg.
2017 F150 XLT-XTR - 5.0L, 4x4, 3.55's, E-locker, xtr chrome package, fx4 off-road package.
20/25 imp mpg