Leon 1M 1.6 105KM 2002 - Ignition loss, does not burn for the 4th cylinder.

Hello, I am struggling with a problem in a leon, stop smoking on the 4th cylinder, the situation occurs only when the car is running at idle speed and then the check engine indicator lights up and flashes, while driving it never happens, after clearing the error even on a fired engine immediately starts burning on all cylinders. The car has gas.

I exchanged;
candles
wires
coil
gas controller
and checked compression on all cylinders.

What I determined:
that the ignition system is not to blame because I changed everything and the signal to the injector suddenly disappears ground control for the 4th injector, after clearing the error the signal returns. I checked the cable between the injection and the controller and it's ok, and there is nothing along the way. What could be the reason why the signal disappears suddenly?

Postpone injection, you have to eliminate the injection itself.
The same situation is on gas and fuel.
Leak collector.

Try to replace the injectors from 4 to 3.

The same situation on gas, because the computer takes gas from the fuel injection signal, and when the signal is missing, and 4 gas injector is not. The question is whether a damaged injector can cause the ECU to switch off the signal? But also on the logic of taking it when it comes to gas, the gasoline injector does not work and yet the signal is lost.

Any errors in the ECU, what does the probe see?
What engine designation?
When the driver sees the loss of ignition and it happens too long, it can cut off the injector control on the cylinder that is not working so that the catalyst is not damaged.
You will clear the error and believe that the fault is removed.
What was the pressure for cold and warm.
I have already done this before and the reason was a burnt valve.

Errors only and exclusively related to the loss of ignition, I observed that you can actually hear how it starts to stop and then the check engine light comes on and it does not go to the 4th cylinder anymore, but why it happens at low speed and when driving ok? are the symptoms of the burnt valve not present at higher speeds? As for pressure, it was checked on a warm engine and it was on the cylinder 1i2 16 and 14.5 3i4.

AUS engine designation

You just don't usually see the signs of ignition falling out at high speed.
Remember that ignition loss is not only a lack of spark. There can be several reasons, such as insufficient compression, poor mix composition (too low, too rich), and there are many reasons for this.
The lack of injector control is in this case the result of the ignition falling out and not its symptom.
You wrote that you can hear that it begins to interrupt and then the control lights up, i.e. it is as I wrote above and it will also be seen in the measuring blocks where the ignition loss is counted, that before this cylinder stops working, the ignition loss is already registered.

And another question based on what (what sensor) the driver "sees" the ignition loss?

There is no special sensor that is only for that.
Measurement of time between each cylinder - shaft, shaft sensor.

I will replace the driver, because I have another one, and then you will have to start checking these valves.

Replacing the engine controller has brought the expected effect, so far it is driving well.