Golf 2 jerks extremely?

Good morning,

My Golf Mk2 with the NZ engine (1.3l catalytic converter) has been having extreme problems for a few days. It sometimes jerks extremely violently. What I mean by that is: sometimes it drives without problems, even long distances; sometimes you're afraid you're about to break down because it jerks as if the engine has completely turned off for a second or so. When it's in this state, it often loses idle and either stalls or runs very unstable.

The ignition is completely new; about a year ago, it received new ignition cables, a new ignition coil, and new distributor and rotors. The spark plugs were replaced in May 2021. I must say, however, that the cables aren't from the best manufacturer (Stark Automotive), as nothing else was available at the time.

I've already checked the thin vacuum hoses, and they're leak-proof. I still need to check the thicker ones, like the one to the brake booster.

I tested a few cables that might be the problem, and then I had one in my hand. I unplugged the connector and re-crimped it properly. At first, I thought that would fix it, but on my drive to work, it started jerking again.

The blue temperature sensor is also new