Check the power brake booster and vacuum system, which can make the brake pedal push back and raise engine speed. Also check the throttle position sensor and a sticking throttle cable. With the engine off and cold, lubricate the throttle cable up to the housing, pump the pedal several times, then start the car and confirm the idle returns to normal.
The owner of a 2002 Chrysler Sebring says the brake pedal pulls back when braking and the engine revs high at startup, and asks whether the repair is expensive. The expert asks whether the pedal pushes back or becomes stiff, and suggests a power brake booster or vacuum problem that could also cause the high rev. For the high idle, the expert suggests a throttle position sensor or sticking throttle cable and recommends lubricating the cable with the engine off and cold, then testing whether idle returns to normal.
