I have a QqQ GC-MS, in which pesticide residues are analyzed, the multimode injector is used with a solvent vent injection method, it has been reported that the peaks come out without shape and that the repeatability is poor, however when injecting into The rear injector has not presented any type of problem, which shows a problem in the multimode injector, no leaks have been observed in the injector components and it was thought that it was a problem with the EPC electronic board, however When changing the component, the problem persists. In addition, negative flows and pressure problems have also been evident. My colleagues and I do not know what the fault could be. I would like to see your opinions regarding what the root of the problem may be and possible solutions, thank you.