Possible causes of a crazy engine?

My car started becoming crazy all of a sudden. The engine keeps:

• stalling out of nowhere even if i am waiting for the traffic lights not doing anything it just stalls by itself
• for the same fuel pedal press, it keeps vibrating like one keeps pressing and releasing the gas pedal violently on the first gear making the whole car vibrate, except it does this just without anything
• sometimes when i press the gas pedal, it takes it some seconds to realize i did so, so pressing the gas pedal doesn’t do anything for like 10-15 seconds(no engine sound, no acceleration, no nothing as if it is not even pressed) and then it starts accelerating after this time it spent like it was thinking 🙂

The strange thing about this is that it is completely unpredictable. It sometimes does this(actually a lot of time) but some other times it just drives very smoothly. Sometimes it does so when the engine is still cold and this disappears when it warms up, but some other times it doesn’t matter whether it is hot or cold. Not to mention that the engine check light keeps blinking every 2 or 3 seconds. The car is Fiat Uno 2006 if this makes any difference and it has fuel injection system not a carburetor, so what could be the cause of this craziness and how to diagnose it?

UPDATE: I had the codes read. What was present was P0105