there is a screw on the manifold inlet for air under curburator... when i bought it sounded heavy as someone had replaced the original screw with some replacement... the car engine also gave vibrations but when i changed that screw with original the engine started running smooth... i want to know how tightly should air screw closed and how does this affect the engine... if someone loose this screw where can i find this screw as it is not easily found in the market
