A flashing check engine light almost always means the engine is misfiring badly enough to damage the catalytic converter. Ease off the gas, skip hard acceleration and towing, and get the car checked today. If it shakes hard, loses power or you smell something burning, pull over somewhere safe and stop.
A steady light means the car's computer stored a fault. A flashing light means it is watching misfires happen right now, at a level that can do damage.
When a cylinder misfires, the fuel it was given does not burn in the engine. It goes out into the exhaust and burns inside the catalytic converter instead. That makes the converter run far hotter than it was built for, and it can be damaged on a single drive. It is one of the most expensive parts on most cars, which is why the warning gets louder.
P0300 means misfires in more than one cylinder, or the computer cannot tell which one. P0301 to P0308 name the cylinder: P0302 is cylinder 2. Knowing the cylinder helps a lot. A common shop test is to move that cylinder's ignition coil to another cylinder and see if the misfire moves with it.
A scan cannot see whether the bulb on your dash is flashing, so the app asks you. Tell it the light is flashing and the answer moves to Stop driving soon, no matter what the codes say.
Only gently, and only as far as you need to get somewhere safe or to a shop. Keep your speed down and skip hard acceleration. If the car shakes hard or loses power, stop driving.
The flashing can stop when the misfire eases, but the fault is still there. The light usually stays on steady afterward, and the misfire can come back the next time you accelerate hard.
Yes. A steady light means a fault was stored. A flashing light means misfires are happening now at a level that can damage the catalytic converter.
Estimates only. A mechanic should confirm. If the car shows a hot temperature gauge, an oil pressure warning, smoke or a burning smell, stop as soon as it is safe.