MAP BELOW !
Death Run refers to the cars races in the desert arranged by Crow Dazzle , a character of the game .
You can find them looking for a cup in the map and generally there are at least one or two race for each region .
The Archangel are version of your car, with a certain configuration (i. e. engine, spike, armor, tires).
Once you reach the circuit , you can choose between a time trial (on the right) and the race mode of the circuit (on the left) .
Easiest way to do this is get the Factotum Archangel (story related) , reach the first Crow Dazzle race , choose the left option (the race mode of that circuit) that enable you to use the Factotum (in order to use the factotum you have to win the race with the first two cars you can select, and only after the factotum will become available to be selected)
The death Run you have to complete is the one on the right of the 1022 scraps symbol on this screenshot