DTC P0350 in Hyundai H1

Good evening, the Van H1 was made the engine because it was overheated, after leaving the workshop, the P0350 code was presented. The code is erased, it looks good for a while and then the fault is presented again, two cylinders are turned off the Cil 2 and 3, one turns off the van, and it turns it on again, it does not present the fault but if the fault code is saved the P0350, I thank you for any help. Thank you.

Look at that the two central cylinders fail to me to check them out

The two coils are new together with the cables of the spark plugs and spark plugs as well.
The fault is presented faster when the air conditioning is turned on.
It is a fairly strange situation.

The strange thing about this is that although the Code or DTC P0350 appears, the coils continue to work, those who stop working or work are the number 2 and three injectors ,,,,, please help.

You tried the injectors in a bank to rule them out because if they work well in bank then it is the signal, the search field must be short