You're not likely to wheel hop in 3rd or 4th so I think you are mistaken. The tire needs to spin. The only time I ever see wheel hop is in the rain in 1st or 2nd.
If it's in 1st or 2nd and it bumps what feels like under your seat, then you have a centre bearing/hangar issue.
It's hard to say what else it could be. Is it a jarring hop? or a bouncy hop? Maybe it's overworked shocks?
Get us more info.
Performance one step at a time.