Fuel Trim Malfunction

As the title reads, i have a fuel trim problem. I have a 06 Tib GT, and two days ago i put a stock manifold that is ported and bored. The opening was bored to 70mm from the stock 56mm, and the insides were bored to 68mm from the stock. Along with that i put a NGM Tri-flow throttle body with a 60mm insert. After two days of driving around i have a CEL. I checked it and it say "Fuel Trim Malfunction Bank 1 and Bank 2". Before i got to write down the code number, i deleted it..and i feel remedial. My guess is that im taking in to much air, which is making my car run rich.

1. Does anyone have any other theories as to why this code is appearing?
2. Can this damage my car? If so, what could it damage?

Thanks for the input, please no negative feedback guys. :3_nosthum