Your car could be could have a number of different systems depending on the year and version.

I presume you have a simple K-Jet system. On this system the prime component for acceleration enrichment is the warm-up (control pressure) regulator. Loss of manifold pressure causes the control pressure to enrich by about .5bar.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician