Cadillac Repair: 1997 Cadillac Eldorado has crazy high rpms, cadillac eldorado, air control valve

Question
I have replaced the ignition coil and the idle air control valve so far.  The car runs crazy!  Normal idle is between 600-800 rpms.  Now it zooms to 1800 rpms.  I pull over, shut car off, restart, runs normal for a while.  Sometimes putting it in park it revs up to 2200-3000 rpms in PARK!  Help!  The mechanic keeps throwing parts in it.  I need to know what it needs soon.  It feels like a death trap.  I will have it on the expressway 70 MPH without using the gas (and it doesn't have cruise control).  I have to keep braking to keep her civil in traffic.  Thank you.

Answer
If you are mechanicaly inclined or know of someone who is, You will need a DIGITAL VOLT/OHM METER, Simple electrical schematics, Test procedures and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture.

I do not have a website so you will have to

e-mail: onlineautohelp@msn.com

in order to obtain the information necessary to fix your vehicle.