I am having an issue with my brakes when I am above 3500rpm on the freeway. The brakes basically almost hit the floor during initial braking. I do not have this problem in city driving. I was thinking it may be a faulty brake booster but would high rpm/speed affect it? The master cylinder has no leaks and I never lose any fluid. I also noticed my rpm at idle is a little high. Could this be affecting the vacuum to the booster somehow?

Thank you honda techs.

 

--->Bad master cylinder or air in the hydraulic system.

The brake booster would not cause such a problem.