Vauxhall Adam rough running and stalling

Those symptoms strongly suggest an ignition issue. Have you checked for specific misfire codes? A faulty coil is plausible given the error codes and connection issues, but confirm voltage supply to the coil pack before condemning it. Is the misfire consistent across all cylinders, or isolated?

The misfire appears isolated to one cylinder. I will check the voltage supply as suggested. If the voltage supply to the coil pack is within spec, is coil replacement the logical next step, or are there further diagnostics I should consider?

If voltage is good and the misfire is confined to a single cylinder, coil replacement is the most likely solution. Given the compromised connections you noted, it's probable the coil itself has suffered internal damage. Best practice dictates replacing the faulty coil with a new, OEM-quality part. Consider a workshop visit if unsure.

Confirmed voltage was within range. Replaced the ignition coil; issue resolved. Total repair cost: 95€. Thanks for the confirmation.