Revving Engine/Acceleration Upon Braking



We have an '01 Subaru Outback. Recently we ran into a problem where our car has begun to accelerate and the RPMs increase upon braking. It appears to be more of an issue when the engine is cold in the morning. The issue just began a few days ago, but it has quickly worsened to the point where I don’t feel safe driving it. Any idea of what the issue could be? We are making an appointment to take it into the shop, but we want to have an idea of what we are getting into before hand.


It could be a problem with the brake booster.
Try stepping on the brake pedal with the car standing still.