If you have installed a new clear pre filter, has it collected debris in it yet? If not, it's probably not a clogged tank screen since you ran biodiesel which tends to keep the tank very clean (unless the bio was made poorly, i.e. non ASTM spec).

Did changing the secondary filter help? There are other items in addition to a clogged tank screen on a 30 year old W123 that can cause loss of power and the shakes.

Problem with going to a dealer or shop is that per polls taken, 50 to 75% are dishonest. That is another good reason to learn to DIY. Breaking things is part of the learning process. We all have to start somewhere.

PM me if you want to stop by and I'll check it out for you. The first 15 min. is free. In that amount of time, I'll be able to tell if it is a clogged tank screen or not.

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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