I have an 84 300TD and I have some issues with the fuel delivery system. I have replaced both fuel filters, injector bypass lines (they were leaking a lot) and the fuel lines in the engine bay and directly in front of the tank. I recently discovered the small (reserve?) tank behind the spare but have not replaced the lines to it. My car didnt have a fuel strainer in the tank. After issues with the primer pump on my fuel pump leaking a lot (now need new engine mount) I replaced that with an updated model. However, my car STILL runs out of fuel! It will be fine and I can drive for 10 miles or so at various speeds and then the thing just runs out of gas (diesel I know)! I have to get out and pump the primer pump for a while, usually til I can feel there is fuel in the lines again, and then I can 'usually' start the car right back up and go again for another 10 or so miles. When it does start back up, its just barely running and I have to pump the pedal a bit until it gets up to speed and then I can go. Im baffled. IP? fuel pump? Posted this problem on the other list with no help. Anyone ever hear of anything like this? I did buy a fuel pump vavle replacement kit, but havent had the guts to try installing it yet.
Help!

Possibly there is an exessive amount of air gettting into the fuel system some how. Is your pre-filter full of fuel with only a small air bubble?

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

Yes, pre-filter is full, with only small air bubble. Looks the same after I "run out of gas" before I pump it back it. Yes, I bled the system until it "buzzed" after replacing filters and primer pump.
There is evidence of fuel leakage in the spare tire area under the reserve tank. Next move is replacing these lines...