Galaxy Fuel Tank Ventilation Problem

Sounds like you're on the right track. If the purge valve is okay, the charcoal canister is a prime suspect. A clogged or damaged canister can definitely mess with the EVAP system, causing pressure issues that lead to stalling and the check engine light. Have you checked the air flow around the canister and the pressure sensor connected to the fuel tank? Those could give you more clues.

I haven't specifically checked the air flow around the canister or the pressure sensor. Where exactly is the pressure sensor located, and what readings should I be looking for? I'm moderately familiar with these systems, but I don't want to start replacing parts without a better understanding of the problem. Are there any telltale signs of a faulty sensor?

The pressure sensor is usually near the fuel tank or integrated into the fuel pump assembly – check your car's repair manual for the exact location. Without proper diagnostic tools, reading the sensor values is tricky. Honestly, with those kilometers and the symptoms, the charcoal canister is highly suspect. I'd recommend getting it checked out by a workshop. They can run a smoke test to pinpoint the leak in the EVAP system.

Took your advice and brought the Galaxy to a local mechanic. They performed a smoke test and confirmed a leak in the fuel tank ventilation system, specifically a defective activated charcoal filter, just as we suspected! The total repair cost, including parts and labor, came to 275€. Runs like a charm now. Thanks a bunch for your help!