I replaced the broken PCV line elbow with the one from this assembly I bought from a Ford dealer (F75Z-6C324-JA). My truck should use the "heated" version of it, but the dealer doesn't have it in stock. The heated version has a three way at the PCV valve side to use the engine coolant heat to warm up the intake air, I guess. I also used the new PCV valve from this assembly.

After I put everything back together and installed it on my truck, it runs like new now. I cleared the engine codes and they never come back again!

Thank everyone for your support in pin pointing this problem. I spent only $20 for an otherwise $500 dealer job.

I love this place!