I'm having the common P2015 intake manifold runner sensor fault. I checked the arm above 3800 RPM and the actuator is working and arm is rotating. Is it the runner sensor on the other end the issue? Does the whole intake manifold assembly require replacement? Lastly, is there any negative impact, beyond fuel economy, if the manifold isn't replaced? This looks quite costly and timely to repair. Thanks in advance for your comments!