I have a question on a 2002 base 3400? At WOT as soon as I step on it I hear a "click-click" occasionally. The sound is coming from the engine compartment. It sounds similar to the click from the engine compartment when you turn on the heat/defrost when the rpm's change, like when I turn on my defroster there is a click and the rpm raises slightly. Anybody have a clue what it is?