2003 GT mystery trouble codes

Here's a strange one. My neighbor's son has a 2003 GT that was modified with a cold air intake, headers, and an aftermarket intake. The car runs fine, but displays several trouble codes (P0443, P0135, P0141, P0155, P0161, and two undefined codes: P1409 and P1451) These codes only happen on start up. I have an Actron CP 9185 Elite scanner and when I clear the codes and run a drive time monitor, I get zero problems! I have driven the car for extended periods and cannot read a single problem with the car running. The minute I turn the car off and restart it, the check engine light comes on. Any help with this issue would be greatly appreciated!