I wouldn't worry about it for now since it's been sitting all winter. If it doesn't clear out though you may have to change out the plugs. I've had plugs go bad when they sit for a long time. If you had your battery unhooked it may take a bit for the ecm to relearn, and give a rough idle for a short while. My 98 GMC does that to me when I unhook the battery to work on it. Almost forgot one other thing, did you check and make sure little critters haven't decided that your exhaust pipe would make a cozy little home?
[This message has been edited by tebailey (edited 03-10-2015).]