Hello proof by putting a MTX liquimoly for the admission in one of those you have a valve dirty or check the plugs of the injectors that are not sulfate, it is with a distributor or with coils if it is with dist. Take out the lid and clean it if it were with coil camcia the cable to the opposit
Do not feel so much to see that the current (spark) is good, you have to check them with a multimeter preferably, if you do not try to exchange the cables with another cylinder and Prubas if it is the same cylinder is the one that fails or is the cylinder to where you passed the cable.
I advise you that any proof that enlance the entertainment step by step to be able to identify where the failure is.