There are several types of misfiring. One is a mechanical misfire which results when the timing belt has slipped a cog. There is another type of misfire which results from spark plug coil being faulty OR the connectors being corroded on the coils on cylinders 1-6. The wires that go to the coils corrode with age and through the vibration of the engine over time. Have your mechanic diagnose which cylinder it is with electronic equipment. If you mechanic does not have that equipment find a mechanic who does. Otherwise you will be replacing parts that may be good parts. Typically its not the coils that go bad (although they do go bad) but the wiring.
most likely misfiring cylinder(s) and/or worn engine mounts.
You engine is probably misfiring. Check your ignition and fuel systems.
Impossible to answer without more information as any number of faults could case a missfire.
You can but it is not a good idea. If your engine is misfiring then unburnt fuel will enter the exhaust. This will damage the O2 sensor and eventually destroy the catalytic converter costing you big time. Stop driving the car until you can have it repaired.
The "Engine system service urgent" message on a Volvo S60 typically indicates a serious issue with the engine that requires immediate attention. It is advised to stop driving the vehicle and have it towed to a qualified mechanic or Volvo dealership for diagnostics and repairs to prevent potential damage to the engine.
You burnt out the clutch probably or it's not in gear properly.
Heater coil
Diagnosis: Engine Won't Start or Run Check related link below
Blow on it. If that doesn't work, turn the engine off.
How to fix a 1991 940 turbo 4 cylinder Volvo to stop running when traveling down the freeway
It could be the ECU engine temp sender, if its different from the guage sender
If by "stop the engine", you mean turn the car off, then the answer is NO!