What happens when engine idle speed is above programmed range?
What happens when engine idle speed is above programmed range? When the engine idle speed is either above or below the programmed range, the ECU prompts the ISC to either increase or decrease bypass airflow. Naturally, as the IAC prompts the throttle plate to open, engine speed increases. The IAC features a plunger mechanism that may be stuck/sticking. What does high RPMs but won't pick up speed mean? It doesn't sound like clutch slipping, if that was the case the rpms would skyrocket while your speed stayed the same. It sounds to me like your vehicle is in limp mode....