The old sagitar 1.6 is not easy to cool after changing the throttle.

Analysis of the main fault causes should be the increase of carbon deposition in the air intake, intake valve and combustion chamber. When the car is cold, some gasoline will be adsorbed, which leads to the lean mixture when the engine is idling, which leads to the unstable idling of the car. So you should check whether there is too much carbon and dirt in the air intake and intake valve. If there is too much carbon deposit and dirt, the cross-sectional area of the air passage will change, which will make the control unit unable to accurately control the idle intake, resulting in too rich or too lean mixture, which will lead to abnormal combustion or engine jitter or even failure to start after starting. At the same time, check whether the spark plug, ignition coil and cylinder line are out of cylinder, and remind the carbon canister whether there is a fault.