The 1991 civic hasd the ECU/CPU well protected from most abuse.
I had a chance to diagram(mostly) one in an attempt to repair it.
I would suspect the failures where coincidence, or the failing(ed)
ECU killed the O2 sensor with too much gas. I would insist
they note the ECU failiure because the cat convereter could be at risk.
They don't like excess fuel.

Terry