It just doesn't work, as if I weren't even pressing it and it happens regardless of the speed. I have to turn the engine off and on again and it'll work for another 3 or even up to 20 minutes sometimes before failing again.
I've changed the oil and gas filters and all the four spark plugs, as well as the oil. I've also cleaned the injection system and the problem is still present. I use unleaded fuel only at 88 octanes.
By the way the catalytic converter notice led is always turned on, and it only turned off like 2 minutes after I changed the sparks and it hasn't turned off since.
My car is a German Chevrolet Corsa 2002.
I've just noticed that the revs get stuck right at the moment the issue occurs. i.e. if I'm driving at 90 Km/h and I shift gears, the pedal will stop responding and the revs will be stuck at
~2000-2500 until I apply the solution mentioned above (turning off an on the engine).
Edit II: Thanks to all that have commented, after many years of intermittently trying to figure this out, the issue was a missing ring that goes on the driver side of the wheel axle, it cost me about $15 USD but it was very hard to find (because my car was assembled in Germany and the only Corsa parts around here are for the model that was assembled in Brazil). I don't know how it's called but it's like a small golden dented ring that just sticks to the axle and without it the speedometer doesn't work (the speed needle would just stay at 0.)
It looks a lot like this:
But the site says it's an ABS sensor ring though...
That was it, I just put it and drove like 100 Km without issues.