I have a 14 scion xb and when I start the car and have it idle it kind of sputters, and when I stop @ say a red light.. it just does it for a couple seconds then quits. Took it to the dealership and everything checked out... any clue as to why it's doing this? Thanks in advance

 

Rough Idle is a symptom of a vacuum leak.. but I don't really know what I'm talking about so just a thought hah.

 

Does the CEL turn on? Get an OBD blue tooth dianostic dongle and check out the codes.

 

Alternator all day. Autozone can check it for free. Takes two seconds.

 

Have you unhooked your battery lately ? On my 06 if I unhook the battery it takes awhile for it to reset