My I recommend you read these posts?
I had this problem when my car was running and will use this fix when I'm back in operation:
The curse of the P0121 Code...
http://www.hptuners.com/forum/showth...rse+P0121+Code
2-3 WOT shift woes
http://www.hptuners.com/forum/showth...WOT+shift+woes