My 04 Pacifica shows problem codes 0456and 0442. I believe both codes relate tosmall EVAP leak(s). Would simply changing the gas cap be the best place to start solving this? There has been no noticable change in the car's performance since the light came on.
Thanks in advance

 

Usually there is not a notiable change in drivability. I would start by checking the gas cap and making sure its tight. Check and see if the o ring around the gas cap has any cracks in it. if it looks good thats probably not your problem. next check all the evap lines and make sure they don't have any cracks in them. very smal splits and cracks can cause this problem. if they all look good you probably have a bad nvld pump. but i rarely see nvlds go on this model.