wonÂ’t rev above 8000 RPM in gear

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ok so i did a fuel pressure test and during the test I revved the engine And the minimal hesitation That was present during reving on a normal basis has gone it hesitates while rubbing in neutral at around 8000 RPMs but during the test it was gone so i Hooked up the regular fuel line and the hesitation reappeared the hose doesn’t appear to be kinked it is a rubber hose covering a harder plastic hose neither one appeared to be Kinked what do u thing i should do next