The brief
The Scirocco was struggling to start when cold, stalling intermittently, losing power under harder acceleration, and the owner could hear faint whirring noises from near the fuel tank. Four symptoms, all pointing at the fuel pump.
The fuel pump lives inside the tank and pushes petrol up to the engine at a set pressure. When it weakens, it can't build pressure quickly on a cold start, which is the long crank, and it can't hold pressure steady, which is the stalling and the power loss when you ask for more. The whirring is the pump's bearings wearing. A pump giving you all of that is a pump on its way out.
The diagnosis
A pressure test confirmed the in-tank pump wasn't holding rated pressure under load, and a scan turned up a fuel pump electronics fault to go with it. The whirring noise lined up with bearing wear in the pump. The fuel filter checked out clean.
That's a replacement, not something you nurse along. A weak fuel pump only gets weaker, and the next stage is the no-start on the driveway.
The work
System pressure was released, the rear seat came up to reach the in-tank assembly, and the failed pump was lifted out. A new VAG-spec pump went in with a fresh seal, sealed back to the tank with new rings.
Then the system was primed, the engine started, and the fuel pressure read on the gauge across idle and load to confirm it was holding spec, before the trim went back.
A road test confirmed it started cleanly, idled steady, and pulled away with the power back.
The outcome
Normal half-second crank, no stalling, the power back under acceleration, and no whirring from the tank.
The Scirocco went home running cleanly. A failing fuel pump gets steadily worse and then strands you with no warning, so acting on the long cranks and the stalls meant a planned fix rather than a tow off the side of the road.