Car stalling when at a stop sign or low speed and turns off, and it also shakes. I just replaced the runner control valve with a used one and new retainer washers from a online auto parts store for my car. Could the shaking be caused by the coolant that came out when I removed the HVAC heater hose? I haven't replaced the coolant. And also would anyone know how to extract a longest screw of the intake manifold?