1996 Ford Escort EVAP Canister Control Valve

I have replaced my EVAP Purge Valve and all the parts on the EGR SYstem. And the code keeps coming up for the EVAP Purge Valve and the EVAP Monitor isn't coming online. I have everyrthing hooked up properly, I am wondering if my gas cap is no good since it is the OEM Cap, or is my canister itself bad. I first was having a problem with my EGR system where the code EGR Insufficient Flow code kept appearing, so I changed the EGR Valve, The Pressure Sensor, and The EVC. But I am thinking if I don't have a tight enough connection on the pressure sensor, would that relate to the EVAP system? Or would the intake port for The EVAP Purge valve on The Throttle Body be gummed up bwith alot of carbon deposits? I am almost pulling my hair out with this EVAP problem so I need some help here okay guys?