villager engine surging

I have a 93 mercury villager that the engine is surging on. The problem does not occur all the time. It is most noticeable when you are decelerating off an exit ramp. After the vehicle has warmed up it can be noticed on idle, it will go to a high idle then come back down. Does anyone know what would cause it. Also, it has automatic seatbelts, and the tracking is stripped out when can this tracking be found.

TPS sensor check the haynes manual.

Would this also hold true for my 94 Villager? I just changed the plugs, wires, cap, and rotor last night, but when the engine is cold the idle still surges even to the point of stalling out the engine. The unburned gasoline smell is no longer in the exhaust though :smile:. Do I need to check the TPS sensor? Other thoughts? Thanks.

Chris