95 ford probe want idle after warming up - 1995 Mazda 626

When cold idle is going, listen to intake manifold with hood open. This will involve getting real close to the intake side of the engine. If you hear a whistle or air draw from anywhere around the intake, there is an air leak to the engine. The intake manifold gasket maybe cracked allowing air to bypass the intake sensors at cold when the gasket is closed. But when it warms up, the gasket allows air to bypass the intake and causes a stumble, pause at partial throttle or a wondering idle. If you increase the idle speed, it confuses the cpu and causes the engine to run eratic.