failed emissions

Need some help with my mustang. Its a 97 v6 3.8 Took it for a smog and it failed. I got codes: p0443 EVAP purge control valve CKT malfunction p1131 no description p0171 System too lean (Bank 1) p0174 System too lean (Bank 2) How can I fix it? Can I do it myself? What is OBD system check...

i took my 87 5.0 5spd to emissions and it failed idle, it was 1137 and the limit is 220HC, and cruise it was 160 and the limit was 160, CO(cruise) was 0.03 and the limit was 1.1 Co(idle) was 0.04 limit 1.2. i tried the guarantied to pass emissions by CRC, engine has new autolite 25's, new cap...