hi there this is my first post on here,i have a 57reg focus st2 with stage 3 mods,whats happening is the idle takes a few moments to settle after revving the engine,the rev counter needle jumps about then it will settle and idle ok,this all started after a garage fitted some rs injectors,i have taken the lower inlet off and can not find any cracks and sprayed brake and clutch cleaner everywhere when running the car,i have no fault codes either,it really is annoying,has anyone got any ideas before i have to take it to a garage,thanks mark.