Rpms increasing on its own and slight acceleration on its own then idles when it comes down

What is your question?

Hi my expedition will turn on and will shoot up to around 2000 rpms and will slowly decrease and when u put it in drive or reverse it will go without any gas the same thing happens when you drive and when I slow down or stop the rpms will stick at around 1100-1200 rpms as if it’s accelerating on its own and when it finally drops below 1000 the car will idle for a while

What makes this problem better or worse?

It’s worse the higher the speed

How long has your 2003 Ford Expedition had this problem?

A couple of days