98 GA V-6 High Idle

Merry Christmas All. My daughters GA came home last night with I can describe as a 3000rpm high Idle. She went to go to work and the car is stuck at 3K. I asked her when this happened -she said when she came home last night put it in park and it was roaring. I don't hear this til later of course. Question--what should I be looking for- I started it up went right to 3Krpm -I stepped on the gas to see if anything was holding her down looks OK-It has high milage--its Christmas Eve and getting dark and cold on the East Coast--I'll check it tomorrow. A few leads will be appreciated.

Look for a vacuum leak. If it came on suddenly then there is a good possibility that one of the lines has broken and letting air into the system from an inappropriate location. The car has high mileage and the lines tend to rot and break. The other possibility is a leaking intake manifold gasket. This will cause a serious vacuum leak and cause high idle.