Have had to rent a Toyota Corolla while my Saab 1992 900 Turbo is being fixed. Battery died and jumped it with cables ? it started but wouldn’t go over 2 mph for about twenty minutes ? icon on dash on (rental agency said engine needed looking at!). Turned it off, then on and suddenly engine was functioning and hi beam which had never worked before ? worked. Gremlins?
It’s a rental. Why as why? Take the demon car back, and ask for a reliable replacement. Was this a ‘rent-a-wreck’?
It sounds like it went into limp mode. It may never cause any trouble or it might go out next time you start it.
[i] wouldn't go over 2 mph for about twenty minutes[/i] ????? You spent 20 minutes with a car that would not go over 2 mph?
For what it’s worth it was either a bad battery or a failing alternator or both. Your cost is nothing.
It’s not your job to figure out what’s wrong with the car. Take it back to the rental agency and get a replacement car. You’re paying for the use of a functional car, not one that’s broken. You already have one of those.
Take the Corolla back and get another rental car.