Just had fuel pump and water pump replaced a week ago now when a drive it on the highway it runs fine soon as i hit a red light in the city or start to slow down it starts idling really hard and feels like it want to stall when ever i come to a full stop i have to put it in nutuarl and rev the gas so it does die and the engine light comes on could this be a spark plug and wire problem. Im lost cant figure it out