[&o]

 

The idle speed is controlled by the IAC valve. If the speed is too high, there is a possibility that the IAC may be bad, the throttle valve is not closing fully, or there is air leaking into the intake somewhere after the MAF. Being that the engine is misfiring, I would suspect that an air leak after the throttle body is causing a lean condition and high idle. Check all air/vacuum hoses for leaks, also you may want to check the air boot between the MAF and throttle body for leaks, and for sticking throttle linkage that is holding the throttle valve open.

 

if it's missing you might want to check the plugs and plug wires. Also this is a guess if the engine light is on you might want to check if the Throttle position sensor is broken.