My car was idleing really high in park sometimes and sometimes would not. Also it would jerk when shifting into gears too. Today tho the brakes are really stiff and really hard to push down. ( new brakes added 2 weeks ago) When i start the car the engine is surgeing/ pulsating and pushing the car forward on its own. I belive there is a problem with the vacuum seal or valve. Also seen it could be the brake booster, master cylinder, or throttle valve. Any help or suggestions is greatly appreciated. Thank you!