Throttle body!!

I have a 03, v8 Lincoln Ls. My car went into fail safe mode so I took it to the local garage and the said it was my throttle body and ford had to install it to program it. I ordered a used throttle body and had ford install it. Of the course the same thing happened it went into fail safe mode however it only did it once because I try to keep it below 1,500 rpm. I took it back to ford and they said the throttle body I got was bad. I then took it to mideke and they ran codes and said the same thing. They also said I shouldn't put an after market throttle body in because of the programming issues it has. I've been doing a lot of research and it seems to be pointing me in the direction of one of my sensors is bad. However it could very well be my throttle body? Please help

What is the exact code that you received before replacing and after replacing the throttle body? Very seldom will a diagnostic code state that a particular part is bad, but rather they point you in a general area to start diagnostics.

-Rod