Speed differential kills on the highway. Loss of ability to accelerate can quickly get you in a dangerous situation where it’s very hard to get to the break-down lane, for example, if you are in a middle lane and traffic is passing on the right and left as you continue to lose more and more speed, now people are swerving to get aronund you, etc.

Ford knew this was dangerous. Their own legal team rated it as a “FMEA severity 10” fault which is the highest severity fault which “effects safe vehicle operation and involves non-compliance with government regulation without warning.” [1]

[1] - https://accendoreliability.com/understanding-fmea-severity-p...