Take off the fuel filler cap when it's quiet and listen for a "swoosh". If you get a swoosh, the vent is blocked and that may contribute to difficulty getting fuel to the IP. Leave the cap off and see if you can get the engine to run normal, then clear the tank vent later.

Edit:
Your 240D is not driven regularly it seems. From day/ night temperature differential, moisture condenses at night when the tank cools off, this water accumulates and algae grows and clogs your strainer and tank vent. Try to get it running from a 1/2 gallon soda bottle of fuel. If you have no trouble doing that, you have more work to do to the tank.

My 85 I just bought sat in a garage not driven regularly and I have an algae problem also. The fuel filler cap was full of rust on the inside. Took apart and cleaned the black algae off the inside of the fuel sender today. I have Startron in the tank and it will slowly kill off the algae. I blew through the vent with compressed air a few times already but it is still clogged.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked