مضخة الوقود تسحب هواء

The pump drawing air rather than fuel, from a low tank, a leak on the suction side, or a failed pickup. Air is compressible and fuel is not, so a pump ingesting air delivers erratic pressure and cavitates — which also damages it.

The signature is pressure that fluctuates rather than falling steadily, and symptoms that follow the vehicle's attitude and fuel level. A clear section of line shows bubbles, which is the quickest confirmation available. On the suction side a leak draws air in without letting fuel out, so there is nothing to see — check the filter housing seal, the quick-release couplings and the tank sender's O-ring. Suspect it immediately after a filter change, since that is when those joints are opened.