1Z Engine Problems: Troubleshooting & Repair

I have a Golf III 1Z with a jerking/stuttering issue in 4th and 5th gear.
So, I disassembled, cleaned, and reinstalled the metering unit once, and adjusted the injection amount to 6mg per stroke. I also set the throttle valve travel to 0.72V when the ignition is on.

However, the stuttering is still present. I then read through all the threads about stuttering problems here on the forum.
I checked the needle valve lifter, which was running at 3000 RPM. I tapped it lightly with a screwdriver, but there was no change in the engine's operation, so it seems to be okay.
Today I drove with the speed sensor disconnected, and sure enough, the jerking is gone. There are still some slight fluctuations under light loads, but the VCDS software indicates that the torque cutoff feature should be working.

The posts suggest that in this case, with this symptom and a disconnected tachometer sensor, the problem might be with the quantity control unit. Has anyone successfully tried this? Replacing the quantity control unit and then the jerking stops.

Hello,
You just cleaned the point machine, right? Just to be sure: was the rotating magnet easy to turn on its own, and did it have enough clearance after the electromagnet was installed? Was the point machine heavily contaminated?
The values for the MSW sensor and the injection amount should be fine.
If the jerking occurs only sporadically, loose connector contacts may also be the cause (e.g., connections in the engine compartment). Clean them with cotton swabs and contact cleaner or alcohol.
Please check the resistance values of the chemical injection skid (CIS) and the resistance values of the lines from the CIS to the pump. The contacts on the round connector of the ESP cable are counted counter-clockwise. Contact 1 to 3: 4.9 - 7.5 Ohms, Contact 2 to 3: 4.9 - 7.5 Ohms, Contact 4 to 7: 0.4 - 1.1 Ohms.
Best regards,
Herbert.

Drehmmagnet ist leichtgängig und hat genügend Luftspalt. Späne waren zwar drinnen, hatte aber schon schlechtere. Ruckeln tritt immer auf im, am besten spürbar im 4. und 5. Gang.
Unfortunately, I no longer have the car here to measure it.