this is gay i was driving my car and the radiator (top one) hose blew up all over my engine so i bought a new hose and cleaned my engine then i tested to find out that my car now when started the RPMs jump to 3000 (normal on a start) then falls to 1500(normal) and continues to do this as long as the car is running (NOT Normal) and when iam driving it it jerks forward when u step on the brakes. i think its the thermostat in the engine that lets coolant in but i am not sure someone help