Hi HDDP
I really wonder how you know the specific sound of farting into an empty beer can *lol*

I read though the posts and must admit that I didn't understand everything, especially some terms. So if I write something you already discussed - sorry.

For what I know the O2 sensors in the exhaust gives the voltage signal (according to O2 flow) to the main chip which regulates the air/fuel ratio by adjusting the injector pulse. When you said you unplugged the sensors, the circuit is open and most chips then ignore signals from these O2 sensors and produce a standard air/fuel ratio information for injection.
So in this case the check engine must not light. Like it doesn't when the sensors are out of operating temperature when the engine and the sensor heating is cold. But the air/fuel ratio in such an open circuit is always the same whether the engine is cold or not, under load or idle. This might be why your exhaust smells. And maybe your mpg will drop.

I'm not an expert. That's what I remember from school and hope I don't repeat something that has been mentioned before...

Greets