If your Fiero is idling too high or too low, the problem likely lies within the electronic control system. You'll need to troubleshoot potential issues such as:
* Throttle Position Sensor (TPS): A faulty TPS can send incorrect signals to the ECM.
* Airflow Sensor (MAF): A dirty or malfunctioning Mass Airflow Sensor will give inaccurate readings to the ECM, affecting the idle.
* ECM (Engine Control Module): The ECM itself could be malfunctioning.
* Vacuum Leaks: Leaks in the intake system can also affect idle.
* IAC (Idle Air Control) Valve: This valve regulates air flow at idle. A dirty or faulty IAC valve is a common cause of idle problems.
Instead of looking for an idle screw, you should diagnose the problem using a scanner that can read the ECM's data. A qualified mechanic with experience in fuel-injected systems is best equipped to handle this.
