[Baffler]

These 2.0D units had an issue with the plastic shut off throttle becoming distorted with heat, sticking in the closed position, restricting air flow into the inlet manifold. The butterfly valve/plate should shut closed when you switch off the ignition and reopen a few seconds later for the next restart. Check to see if it's reopening fully and free of obstruction.

A new shut off throttle is the answer to the above problem but, as a temporary measure, you can file back the edge of the plate a little so its not becoming stuck/jammed in the closed position.