97BlackSSCamaro#142

well i recently had the clutch changed out ,,a few months after that i had a resonator put it midway between the y-pipe and muffler and i know its not rubbing, well a little more than a month ago i notice a noise kinda sounds like a slight grind or rubbin kinda like somethings against something else,,when i upshift to 2nd and then again to 3rd but not to any other gear,,so i removed my short shifter, well about two weeks after taking the short shifter out the noise went away, well tonight on my way back home from being at a friends garage almost to the house the noise comes back,,and i cant figure out what it might be,,,,,any suggestions on what to look at or to check????