What make a 2.2 liter engine idle high?

A 2.2-liter engine may idle high due to several factors, including a vacuum leak that allows excess air into the intake, causing the engine to run lean. A malfunctioning throttle position sensor (TPS) can also lead to incorrect throttle readings, resulting in increased idle speed. Additionally, issues with the idle air control valve (IAC) or a dirty air filter can contribute to high idle conditions. It's important to diagnose the specific cause to ensure proper engine performance.