help!!! shes bunny hopping at 30-40mph???

hello all
got a series 3, 88, 2.25 petrol ,1980, wether hot or cold and with full tank of fuel or little fuel she bunny hops when i put the accelerator down at about 30-40mph take foot off gas reapply it and it cures it sometimes, she just had full service still didnt cure it, changed coil, still no, redex down the carb and in fuel still no, does not do it all the time just when she feels like it???? can anyone help me cos im running out of things to check???

This can be a lot of things but i would try referbing the carb next.

Ps
Check the fuel bowel on the lift pump as well

carb replaced and all is running smooth as a babies bottom now
thanks all