The throttle of the old Jetta failed.

1, the valve clearance is wrong, so readjust the valve clearance.

2. The valve stem is bent and the valve is replaced.

3. Bend and replace the valve ejector rod.

4. If the valve conduit is broken, replace the conduit.

5, nozzle bite to death, nozzle calibration, atomization is not good to replace.

6. The oil pump pressure is low and the rocker arm is short of oil. Check the oil pump and camshaft.