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).