Vehicle Stability Assist
1 make sure you did not accidentally turned if off, if so turn it on.
2 check for low tire pressure
3 you need to scan it.
if it is turned off or detects a fault it will lower vehicle speed, this in normal.
it could be nothing or it could be serious, might need a steering angle sensor, only reading the codes will tell.
So the plot thickens……a mil would trigger the vsa. With that the vsa is more than likely working normal.
miss fire nbr 2 could be sparkplug or coil pack
could be crank position sensor, I would think you would have more problems than 1 cyl misfiring.
plugs cheap, coil pack swap cost nothing then position sensor.
or
could be a sucked vlv hole in piston or hole in block I would start with coil pack
Pull the spark plug cover off and start the car. 2nd from the left is #2 cylinder. Unplug the ignition coil while its running. If there is no change in the misfire and the engine still runs like crap swap out the coil