98 Taurus fluctuating Idle

I have a 98 3.0 LX and when at Idle it stats at 1000rpm then jump up to 3000rpm then down to 500rpm and almost dies but never does, then back up to 3 and so on, also recently when driving it will also feels like it is trying to rev up a little. I changed the spark plugs and checked the vaccume lines and I am wondering what is next. Any help would be awsome.

Could be a dirty or failing MAF or dirty or failing IAC. You should try searching the forum for those two items to research symptoms others have had and what they've done to remedy them that worked.

-Rod

Sounds like you need a new throttle position sensor or possible air bypass valve.