rough idle after fillup

I have a 2001 Hyundai Elantra that for the past 6-8 months has been idling rough after each fillup for the 1st 3-5 miles. Idling smooths out after this initial period. Acceleration & running at higher RPMs is fine. I've changed plugs, wires & regularly change oil, filters, etc. Have also used gas treatments on occassion to no avail. Am wondering what might be the cause. Appreciate any thoughts/recommendations!

try not filling it up and see what it dose over fill can get in you pollution canaster. i belive theres a relay that's going bad these last few years also.

Scrapper,

Appreciate your feedback! Didn't quite understand the recommendation regarding the "pollution canaster"...can you elaborate? And what relay specifically could be bad?

Thanks so much!

Ed

charcoal canister.