Help plz

Hi, i Need some help with my gtd.
The Car did go good but now it doesnt going good

Iam gonna try to sell it but it just dies when i drive, it goes really good and then it starting to die. Have checked timing, tried to bleed.

From the filter i have visible fuel line and i see much bubbels when the Engine going plz help🥺

on a diesel bubbles are bad and the direction they are traveling tells you where the issue is.  To the Engine, fuel line to the filter and or the clear line including the banjo fittings.

From the engine to the filter then a leak in the IP, hose connections from the tank/gravity valve including the banjo bolts.

You may need new crush washers, on both sides of the banjos, and or a new clear line.  I had one leak air after it had about 10-15 years on it.