Loss of power when driving

I have the Workhorse 8.1L, but not W24. Few years ago I was driving on the freeway and suddenly heard a loud sort of backfire noise and dropped to about half power. Limped off the freeway at the upcoming exit and went to a repair shop. The O2 sensor in the exhaust pipe had popped out. It was actually hanging down from its wire, creating a hole in the exhaust pipe up in the front half of the chassis. You might want to get under the rig and inspect the whole length of the exhaust pipe.
Another time I was driving on a different freeway and suddenly lost all power. That was a fuel pump failure. No warning. It worked, then it didn't...as Grit dog stated.