While i was driving on the freeway my car all of a sudden got REALLY LOUD so i pulled over amd popped the hood, there is a hole with threads right where the exhaust connects to the engine , and it's just blowing out hot air , what is supposed to go here? Plz help

 

Front Oxygen sensor.

​​I bet the sensor is hanging off of the wiring harness by the connector. Those connectors usually require a firm tab press to disengage the connector.

You are looking for a sensor device similar to the picture below, dangling with the connector end connected to a matching connector.

Someone may have connected it to the connector, then installed it. This would have put many turns in The wire as it was threaded into place, creating a constant force to unthread it. If it wasn't completely tightened down, I suppose over time it could loosen. I don't see any evidence of it having broken off because there are no leftover threads in the hole at least not from this angle.

 

100% agreement with derf. If that thing had been installed properly, it would have NEVER blown out! I've never seen that happen before.

 

I had that happen to my work truck out of town. They get really loud!

 

Ok so i found both 02 sensors and they are still connected and scewed in, i ended up getting a metal plug and plugging the hole.

 

Hmmm
Could you take a few pictures from a different angle, not above? Whatever was there like we should be put back.

 

K , so i when i had someone replace my catalytic converter they got one that was for a different year than my 05, that hole is where an oxygen sensor would have gone, instead of right up against the engine on the exhaust manifold

 

As long as it runs good and isn't throwing any codes, I'd say mission accomplished!