Why 91 Toyota Cressida idles high?

A 1991 Toyota Cressida may idle high due to several potential issues, including a malfunctioning idle air control valve (IACV), vacuum leaks, or a faulty throttle position sensor (TPS). A dirty or clogged air filter can also affect airflow, causing the engine to idle higher. Additionally, if the engine control unit (ECU) is not receiving accurate signals or is malfunctioning, it may lead to improper idle speed. Regular maintenance and diagnostics can help identify and resolve the issue.