im going to give you the complete replacement instructions and let me know if theres anything you did different.
they only make one motor for the mpv with one timing belt. so the problem has to be the installation, or a worn pulley somewhere.
Removal Note: Timing belt pulley lock bolt
like i said, if you did anything different please tell me so we can figure something out, and if there are any other questions let me know, if there is nothing different between this, and what you did, we'll figure something out