Motor force loss

Ok .. I would like to ask you if the coils can be exchanged, that is, can I use the coil that works in 1-4 and place it in 2-3?

When the spark plug cables are disconnected, the electric arc that emits the coil is heard near it, it is not enough to know that the coil is good?

You should be able to change them, but always not only changing the cables to the spark plugs but also the cables that come from the central to the coil, all this if you have two independent coils.
If it is a module where it has two talls inside you will not be able to exchange the cables only because it has a single input connector to the coil, I do not know if I explain.
I attach a scheme where the spoils appear.
The spark test did it when the engine failed or under normal?
Greetings.

The coils are independent, one has the spark plug cables for the 1-4 pistons and the other coil has the spark plug cables for the 2-3 pistons.

I just had the test by exchanging the coils I realize the following:
1.- When disconnecting the cables of piston spark plugs 1-4 the engine goes out.
2.- When disconnecting the piston 2 spark plug cables, change in the motor march is noticeable but does not
turn off.
3.- When the piston spark plug cable 3 is disconnected, there are no changes in the engine.

4.- In all the previous cases, when disconnecting the cable at the level of the spark plug, the electric archos emitted by the coil is heard.

5.- The injectors and spark plugs of the piston 4 were exchanged with 3. To rule out these elements. The results are the same.

The truth is that it is complicated, one more thing, when you change the coils, did you change the cables too? Did you try that the coil-cooked cables do not fail?
Apparently the fault is in cylinder 3, not only listening to the spark jump on the spark plug we can be sure that the coil and spark plug works well, I would take out the spark plug and place it mass its thread can see the spark that generates in the electrode, be careful with the strokes of tension !!!!

Look at the best way to solve your case is the following, disconnect the cable two and put a spark plug or screwdriver and look at the spark, then the same with the three, if you spark then you discard the coil and cable, in this case it changes the spark plugs and proof of again, if you do not want to buy them, just change them and perform the test you already take the test that you already do, but what do you say.