when clutch is ingaged or in nuetrual it stays reved up at 2000 rpms and wont go back to idle rpms. the only way to get it to go down a little is to put in neutral and rev it up a little
My car has a manual transmission.
The causes of high idle speed can be determined via a diagnostic. Engine idle speed is controlled via an idle air control valve (IACV). If the valve is malfunctioning, or even if the fuse to this electronically controlled valve is faulty, the IAC motor could malfunction, leading to a higher than normal engine idle speed. Vacuum leaks can also cause a high engine idle. The engine's oxygen sensor will detect the extra oxygen entering the engine through the vacuum leak which will alert the engine’s computer that the exhaust is running lean, which will prompt the computer to pump in additional fuel, resulting in an abnormally high idle. A malfunctioning throttle system can cause both a high idle as well as an engine stall. A dirty air intake or cracked air intake tube is often the culprit. Although "rare," if the car's PCM (main engine control computer) malfunctions, that can cause a high engine idle, but all other potential causes, of which there are quite a few would have to be ruled out first. YourMechanic can diagnose your abnormally high engine idle during a mobile visit to your home or workplace.
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