2002 Dodge Ram

It could be as simple as a bad fuel cap (but not likely) or a leak in the EVAP system (most likely). These leaks are hard to find because you really can't see them. What I recommend is to have the EVAP system fogged. What the shop does is put fog into the system at a very low pressure. Wherever the leak is, the fog will come out. THerefore you can identify where the leak is.

I don't know what the shops in your area will charge, but if you try to find it without this, you will go crazy.

Let me know if you have other questions.
Joe