i have a 99 laguna i6 valve when driving she seem to pull back as if shes losing power then thrust forward in?

Answer 1

maybe fuel/air problem

after saying that , it's a miracle you have got it to float to experience the problem! well done!

Answer 2

Just one thing, the clutch isn't slipping is it?, other wise the injectors need cleaning/ changing or the bit of kit that supplies the fuel to the injectors is on its way out, you could try a fuel additive to see if this cleans the injectors, good luck.............