I have a weird problem with my Golf 4 V6 2.8L 4motion, 1999. On exactly half tank (correct by gauge, distance and volume refilled), the car brutally loses all power if going uphill or accelerating quickly (most of the time flooring 2nd gear, all the time flooring 1st). The power loss is total and lasts for 1-2 seconds, then all power comes back instantly. I refilled the tank and the problem totally disappeared.
The car seems to have the fuel tank in two parts due to the central drive shaft, but I can't find how the two communicate, as the symptoms seem to be linked to that property.
This is the most detailed schema I could find : https://volkswagen.7zap.com/ImgsWatermark/images//Bilder/194/194201070.png
The device between 7 and 8 (right part on the picture, left side of the car) looks like a gauge but I don't see any means of flowing fuel between the two halves.