Throttle Control Warning Light On problems of the 2005 Chrysler 300

While driving my 2005 Chrysler 300 the throttle body control light on the dash comes on. And the car starts running ruff looses power and speed till it comes to a complete stop. I have replaceed the throttle body and the main computer without any change. My machanic says the problem is in the wiring harness. They contacted the dealer about getting a new wiring harness and was thol the wiring harness was disconued an they no longer make wiring harness for this car +and that it couldn't be repaired.

After leaving my vehicle parked in a garage at the verizon center in washington, DC for approximately 2 hours. I started the vehicle and proceeded to exit the garage. As I left the parking space the vehicle was making a very loud noise as if the engine were going to fall out. I depressed on the accelerator and the pedal went straight to the floor board. I was going up an on ramp and the vehicle coasted backwards. . Luckily there was a open space that my vehcle could safely back into. Immediately after the electronic throttle warning light illuminated. My vehicle was later towed approximately 2 days later due to it being parked in a busy garage. The vehicle was taken to an independent mechanic. After taking the vehicle in they advised me that the throttle was not opening. The vehicle was repaired by cleaning my throttle body. The manufacturer was not contacted. The failure mileage was approximately 114,000. The VIN was unavailable.