im getting a check engine code of 40.. the purge control.( auxillary port valve) . i dont know exactly wehre that is located though.. can any one help me out.. and any idea about what exactly is the problem with it...

the problem i having cause my car not to go past a ceritian rpm ( 3000-4000)... i've noticed lately though that when i drive at night and its kinda chilly out.. i wont do it.. it bugging the crap out of me cause i wanna get this fixed...