What would cause P1521 and P1522 on 1995 Mazda Millenia 2.5 and make the car run poorly... Car runs good until heating up?

The P1521 and P1522 codes on a 1995 Mazda Millenia 2.5 typically indicate issues with the Variable Intake Manifold (VIM) system, particularly relating to the position of the intake manifold runner control. When the engine heats up, the manifold may not be functioning correctly due to a malfunctioning actuator, vacuum leak, or a faulty sensor, leading to improper air-fuel mixture and poor engine performance. This can cause rough idling, reduced power, and stalling as the engine's operating parameters change with temperature. Checking for vacuum leaks, inspecting the actuator, and ensuring proper sensor function would be essential for diagnosis and repair.