Engine idle climbs to 3000rpm+ when I put it in park!
Another menacing and intermittent issue that no mechanics have been able to pinpoint or fix for me:
Sometimes, when I put my 98' taurus (3.0L) in park, the engine idle climbs to 3000+rpms until I kill the engine (turn car off). If I put it in Drive when this happens, you can imagine what results - can't be good for the tranny. Anyway, this happens more frequently when it's really hot outside and rarely during the winter. If it does happen during the winter, it's because I've accelerated really hard (this is a 98' Taurus Wagon here, so really hard is probably pretty normal compared to any other vehicle) at some point during my driving. A mechanic replaced the Idle Air Control Valve thinking this would fix the problem, but it has not...
Anyone have any knowledge as to what might be the problem? *I also get 13mpg consistently in Chicago.