Check engine code P0441
 

I recently installed a new engine, and in the swap also added a dual catch can pcv system, and a supercharge. I did the EcuTek tune that came with the supercharge. The car runs great, and did for the first few hundred miles, then this P0441 code showed up. I thought it might be a loose gas cap, so i tightened that up, reset the code, but it came back on. Im not sure where to go next to see if i can figure out the problem. Any suggestions?