That's your charcoal canister (vapor canister)
Just fyi - you've posted this in the new members section. To get more eyes on your posts (since you did the new member post already), you can post in the main forum.
Scott
'
Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole
But there ain't nothin' wrong with the radio