Sounds like fuel contamination. Put a whole bottle of algaecide in the tank and just live with it till almost empty. That'll kill the bugs. Then pull the fuel strainer and clean and gunk on the filter.

Clean fuel from a busy station, an application of Diesel Purge and new fuel filters is next. You might have to remove the injectors to clean them if all this doesn’t work.

I recently went through the same drill due to an algae bloom. PITA!

PS Your post does not say your location but if you're in the NE and heat with oil I'd siphon off the treated fuel and add it to my home heating tank if you don’t want to wait till the tank level is low. Good luck,

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Toblin

'79 300D, "Liesel von Diesel", 235K

I kid proofed the house....but they still get in