Volvo S60

A flashing check engine light means you have a severe misfire. Have it scanned for codes to see what cylinder is misfiring. Once you get the cylinder number, I would suspect a bad ignition coil. What you can do to verify this is swapp the coil with another coil on a different cylinder. Have the fault codes erase and road test. If the misfire follows the coil in the cylinder you installed it then the coil is bad. Keep me posted please.