Just wanted to post a tip on the high RPM's while in neutral or park. My wife has a 2001 Ebony with 67,000 miles on it. For the last year or so the Rpm's have risen from 1,100rpm's up to 2,500 while in neutral. I replaced the Idle control valve, cleaned the EGR and IAF only to have no change in the idle. I decided to reset the computer in the vx by leaving the battery disconnected for 30 min. or so. It solved the high idle problem and the RPM's have gone back down to 1100 and 1400 depending on the weather. I did this about 6 months ago and have reset the computer twice since then after the rpm's worked thier way back up to 1,800 rpms.
In a nut shell, try disconnecting the battery b4 you replace the control valve or clean the other components. It might save you a few bucks.