What causes idle speed to increase in neutral? on 1998 Ford Taurus

After the engine warms up the idle speed will surge when put in neutral or park. I had this diagnosed and fixed a year ago. The TPS was replaced. Even after the TPS was replaced the car seems to hold it's current idle speed when in drive. I'm talking coasting a 1/2 mile with foot off the gas and not losing any speed. About 6 weeks ago the initial problem came back. Is there something else, in addition to, the TPS that should be looked at? Thx

by in Peoria, AZ on September 14, 2009
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1 answer
ANSWER by , February 11, 2010
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