At stop lights after warm engine, idle decreases from 600 to 400 in about a second
I have an 07 explorer, 4.0L. At a stop light, I can feel the engine rpm dropping from 600 rpm to 400 rpm, then back up to 600 rpm. this happens every 3 to 5 seconds. It just started doing that today. Nothing electronic in the vehicle is on. The engine light and wrench light is not on