Jimm 6/30/2012Possible the Intake Manifold Runner Control(IMRC) solenoid is not moving when commanded by the PCM. The PCM knows it is not moving, because there is a built-in position sensor inside of the IMRC. The job of the IMRC is to shorten or lengthen the air flow passages into the intake manifold at the right times for maximum performance, by opening and closing ports inside of the intake manifold. These passages are moved by a cable attached to the IMRC that moves butterfly valves on shafts that run through the center of the intake. You can see the cable which will be attached to a lever and a shaft by looking right below the throttle body assembly on the driver's side of the engine. Follow that cable, and you will find the IMRC. It may even be bolted to the top of the front valve cover. Chances are you need a new IMRC. But you should clean the air intake manifold with carb cleaner to free up the butterfly valves I described. Sometimes what makes those IMRC assemblies fail in the first place, is heavily carboned up intake runner valves that cause undue stress on the IMRC.