Wife drives a 99 Expy. Today she took it through the car wash and when she came out, she said she heard the idle go way up and it would not go over 15 mph on the road. She nursed it home (don't know how long the 15 mph lasted)and I got there and started it up and the idle went to about 2500 rpm at ignition. I put in reverse, then back in park and it dropped down to normal. There was also a complaint about a clunking noise when she drove it. I drove it and it sounds like something is loose underneath when you go over bumps in the road. These are 2 separate issues I'm sure, but has anyone heard of any problems like this. We have had it to the dealer a few times and they find nothing wrong with it. No CE light or codes since we've had it. It's got the 4.6 in it, with 70K on the motor. I'm stumped...

 

My 99 Expy acted very weird on the idle both times when one of the coil packs died on it. One did it under warranty and one not. ***** times the idle was rough - but the first time it was a high idle and the second time low (lower than normal) idle. The second time was worse in wet weather or after a car wash. This may not be the same thing but could be..

Hope this helps!
FF