1995 E150 Help

[O&M]

I have a 1995 E150 Seems that most often when warm, will Idel normal and for a few seconds Idel really high,while in park (highers rpm,)? Also will do this while driving making it feel like it would have a trans problem, jerking almost like it is getting to much gas or not enough at times as the Ideling goes from normal to high regardless of being in park, or driving 65mph? Any help would be great.
Thanks

[ModMech]

It sonds like a vacuum leak of some sort, or posibally a malfunctioning idle air control valve.