Our GM Colony Park has been setting for around a year we bought a fender, a headerpanel, a fuel filter, and a TFI also gave it a tuneup but we're affraid to drive it because last time we drove it around last month starts fine but every time we stop at a light and try to give it some gas when the light turns green and then it would sputter unless we put on the gas pedal alot of times even all the way to the floor sometimes it will shut off and sometimes it would go.

Do any of you might know what the problem is?