throttle positon sensor promblem in saturn sl2

i have a saturn sl2 i started out with a low voltage code i pulled the code replaced the throttle position sensor and now i have a high voltage at the throttle positon sensor i tried to erase it and it comes back need help contact asap cant figure out at loss sometimes car dies with it being in netural

What is the code exactly?

Also, in nuetral, the IAC controls idle speeds. Clean your throttle body including all the IAC passages

po0123 is the code and i already cleaned the throttle body and still it does this and the old code was po0121 and in po0123 it reads throttle position sensor high voltage and the other one is throttle position sensor low voltage

any one have any ideas