My 2005 Cadillac CTS goes into limp mode randomly. It has been doing this since I bought it used with 7,500 miles on it. I have had to the dealer numerous times to no avail. I have tried the throttle body reset procedure, I have tried disconnecting the battery, my next step is to attempt to clean the throttle body. It throughs code P2138 (Throttle Position Sensor), the dealer says that they have replaced the throttle pedel position sensor twice.