u/Evening-Blacksmith-6

I was on the highway this afternoon when my truck (2018 Sierra 5.3 with 6 speed) randomly entered reduced engine power mode and stalled. It would not even attempt to turn over unless I had the gas pedal to the floor but would not start. I checked the fuses. I removed the air intake and was able to get it to start but it was squealing and stalled after about 30 seconds, would not start again. The throttle body doesn’t look very dirty and moves freely. Could this be a vacuum pump or related issue?

Please help!

Thanks