Pontiac Problems? Ask a Mechanic for Answers ASAP
Hello and thank you for your question,If you watch the shift selector at the transmission while having a help move the shiftier back and forth is the selector moving at the transmission?
The problem you are having with the shiftier is a known concern and GM has released a service bulletin dealing with it that involves a frayed shift cable. I have enclosed the bulletin in the link below for your review. Have a look and see if this is what yo have going on with your G6.https://dl.dropboxusercontent.com/u/104923897/Shift%20cable%20JUl%2023.pdf
Okay for this issue I would start with checking the battery to be sure its fully charged and also make sure the connections are clean and tight.
Well if the is not power in the complete car what is the voltage readings at the battery?