Did you hot glue the over pressure valve on your pump? B/c you might have a tiny piece that kinda flaps over every on and then. idk.
To be honest, you might as well just leave it alone. From what i understand after the funky pump, it still works. It really doesn't sound that bad. I would just leave the gun alone. Cut your loses on a botched job.
Well accually, if i was me i would end up taking all the tape off, and finding the damn leak.