Check service ride & Traction contol light on.

Hi...I just purchased a used 1996 Seville SLS and the car shut down (stalls) at lights. I had a diagnostic service performed and it showed a code of P1599. I had a PCM computer installed and a starter for $900. After I picked it up it's still stalling. The Traction Controll light is on and the Check service ride controll is streaming across the display. Do you have any idea as to what's going on here? Also, I hear some crunching we I get in and out from the rear.:runaround: