So it’s a diesel (gas tank confused me…) and it’s basically a 20 year old Sprinter turbo diesel.
Well that complicate things. Break out your wallet…..
That said your description is literally as vague as possible if you’re asking for help diagnosing on the internet.
You suggest that this condition corrected itself sometime within the the tank of fuel, as you said it appeared twice after filling up.
Now you say it affected the turbo but that it still runs.
And the condition clears up at some point and then comes back with a fill-up? Not likely related to filling the tank if it is an intermittent major component failure.
Back to codes thrown and better description of the issue if anyone is to be of any remote help.