rough idle problem,hi think i have an injector fault,when cold if i remove plug from injector 2 the engine rough idle doesnt change when i remove plugs from 1,3,4 injector the car idles even worse. so it seems number 2 injectors not working right.....tried this when engines warm and running right and number 2 injector causes misfire like the other injectors if removed....anyone had this fault...and if it is an injector 2 fault can i change the injector for a new one with the same part number....please help