That's a bummer. Get an aftermarket exhaust and never worry about ASD ever again. That's what I did.
You may have some loose wiring too. Check out the ASD module. Look for the ASD bypass install thread for instructions on how to locate the module. If you're near a dealer take the car in. To verify that your ASD isn't working change driving modes as you cruise down the road. It should get louder when you switch from comfort to sport.