My daughter's camero (6 cyl.) jumps when she stops at red lights.  And then acts like it wants to cut off by spitting and sputtering.  Sometimes it does cut off but cranks right back up.  There is no engine light on.  The spark plugs and wires were changed in April.  We added a bottle of fuel injection cleaner and today she said it ran good.  Should she add a bottle every time she fills up with gas?  

If FI cleaner made a difference, it sounds like the car needs the fuel filter changed. With no check engine light being tripped, the other possibility is that she got some bad gas on her last fill up, or there's some trash in the tank.

Change the fuel filter, run another bottle of FI cleaner (I'd suggest a bottle of Techron Cleaner) and see what happens.