I should specify a little more, if the vehicle moves in any way or if any moves or if it is only the problem of idle instability. I would begin by seeing the vehicle data, if there is rich or poor mixture, if the TPS signal is varying even if the accelerator is not touched. It could be a lack of an earth polo or in cases that carry a single oxygen sensor the sensor may fail as in the case of Chevi Monza. The other one that could do is disconnect the MAP if it has, the injection systems change between countries and could bring another type of air meter. But it helps me a lot to analyze the live data of the vehicle to start diagnosing a failure.