after changing the fuel filter and (finally) bleeding the fuel system correctly, i got it on the road. after about 30 miles of driving, the car began to sputter when i got into my neighborhood on the way home. when i was doing the fuel filter, i checked on the air filter. completely shot. i removed the gasket off the top of the filter housing too. other faults include my exhaust which is about to fall off, and motor mounts which make a terrible knocking noise whenever the car's backing up. i'm just about ready to give up on it. What's going on?

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1980 240D, 197580 miles - "The Stuttgart Stomper"