Mercury Villager: odd transmission problem?...help or advice.?

Mercury Villagers and Nissan Quests were built in the same factory in the US, it was a joint venture. The vehicle is all engineered by Nissan, with some specs laid down by Ford, so some small details are not the same as the Nissan version. The problem you are having can be caused by a bad throttle position sensor, a dirty element in the m airflow sensor, or a dirty sprocket in the distributor under the rotor. The throttle position sensor is difficult to install because of it's location, and has to be adjusted with a voltmeter. It's possible your is just out of adjustment. If you intend on working on it at all, I would invest in a manual from eBay or something.