[ischmitz]

Once the speed sensor goes away the DME heartbeat (fuel signals, spark signals, tach signals) from the DME go away. And the fuel pump stops. The reference sensor is actually less suspect here. It is only needed once at startup but then only get read sporadically.

A lost speed sensor signal or lost power will look identical unless you are able to see what the ICV does when the system cuts out. You really need a data logger + breakout box to accurately diagnose this.