Chevrolet S10 high idle issue with unknown cause on Chevrolet S10

Some Chevrolet S10 owners report experiencing high idle issues due to several potential causes. These include a faulty or dirty idle air control (IAC) valve, which can lead to elevated engine speeds. Additionally, a dirty or malfunctioning throttle body may contribute to the problem. Owners also note that vacuum leaks can introduce extra air into the engine, further increasing idle speed. A malfunctioning MAP sensor has been reported to cause very high idle, shifting problems, and even false error codes. Furthermore, issues with the ignition system, such as faulty spark plugs, can result in rough idling. Lastly, problems with the engine computer may confuse idle speed control, particularly after adjustments to components like the IAC or throttle body. It is advisable for owners to systematically check these potential causes to accurately diagnose and resolve the high idle issue.