I have the engine codes 11,13, and 15 for my 94 eclipse. Any help for a noobie?

Read out said "leak detected. Pressure valve." There is no gas smell in the cab. And this happened after I replaced the valve cover gasket. Read things that say it has to do with the evap? Anyone have a clue what this is about?

Hey guys i need help. My car has been idling really rough, sometimes chugging/choking when driving, and dumping fuel bad. I have fixed several engine light codes already. I changed the MAF sensor, the throttle position sensor, both O2 sensors, and i just keep getting codes. I can't find a vacuum...