Faulty gas cap?

I just bought a 1998 Jeep Cherokee sport with the I6 4.0L engine. 5-speed manual transmission. The day I bought the vehicle, there was no check engine light on or anything but 2 days after I got it the check engine light came on when I started the vehicle in the morning. Got out my scan tool and got it to read P0443. Had to do with evaporative, cant remember the whole thing. Anyway, i thought maybe it was the gas cap since I had just put gas in the night before so I took the cap off and tightened it back up, letting it click a good 5-8 times. Cleared the codes, let the vehicle run for a few minutes to be sure it wasnt going to come back on, shut it off for a minute, turned it back on and the light came back on and has been on ever since. I really cant seem to find any vacuum leaks anywhere or hear any that may be leaking. Do you think it would be a smart choice to buy a new gas cap to see if it takes care of the problem or is there something else I should consider doing? And before someone says to try tightening it again to see what happens, I have done it several times just to be sure. Thanks in advance!

thats a purge code. fuel cap has zero to do with that

The code P0443 is, “Evaporative emissions system purge control valve circuit”. Click on this link for info on the evaporative canister purge solenoid: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800a9ba2 Scroll down about three “pages”.
Your public library probably has a subscription to www.alldata.com. You can go to that Website and get the troubleshooting charts for that DTC code. You’ll need to use a multimeter, too, and the wiring diagrams.