Problem with 05 SRX
 

Hello everybody. I'm new here and I know I should post in the intro section first but I'm having a problem with my girls new vehicle and need some help.
Okay, we just bought a used 2005 Cadillac SRX about 2 weeks ago and yesterday it started to screw up bad. Randomly out of nowhere we went to start it and it was shaking pretty bad and "Reduced engine power" came up on the nav screen. The service engine light and a few others came up on the dash. I was working at the time so told my girlfriend to bring it over to Autozone and have them scan it and call me back. She did and was told that the code thrown had something to do with the throttle body. Thing is the throttle body was replaced about a year ago according to the Carfax. It being under 30 days old, it's still under warranty so we call the dealer where we bought it and made an appointment the next morning. It wouldn't exceed a certain mph on the way there. Later that day they tell us that they have no idea what's wrong and are sending it over to the Caddillac/GMC/Pontiac dealer. Okay fine. Well this dealership can't find out what's wrong either. They said the throttle body is definatly new and they think it's something electrical but can't find out what. Now the dealer we bought it from is giving us **** about that not being covered under the "limited powertrain warranty" and refuse to give us a rental car for the time being. It's pissing me off because either dealership can't figure it out and there already planning on making us pay for it. Any help would be GREATLY appreciated.
2005 Cadillac SRX
4.6l V8
Just over 50k miles