It manifests only at a certain speed range (40 to 55 kmph): acceleration pedal press isn't translated into car acceleration instantly, but with up to 3 second pause, during which the ICE is revving up almost to the max.

I wanted to record speed, rpm and acceleration to graph that and show at the repair station.

At one visit in a authorised repair station the mechanic couldn't diagnose it (unrelated heavy snowing conditions).

> the model wasn't trained on speedometers.

This sounds problematic and like it explains why the first example image is improperly labeled. There is a general form to dial gauges and the results make me suspect of overfitting. Data diversity is essential. Quality of data matters more than quantity (though you still need quantity).