* Throttle Position Sensor (TPS): A faulty TPS sends incorrect information to the engine control module (ECM), leading to a rich fuel mixture and a high idle. A bad TPS can cause the ECM to think the throttle is open more than it is.
* Mass Airflow Sensor (MAF): Similar to the TPS, a dirty or malfunctioning MAF sensor provides inaccurate air flow readings to the ECM. This can result in the ECM adding too much fuel, causing a rich condition and potentially a high idle.
* Idle Air Control (IAC) Valve: This valve regulates air flow at idle. A dirty or faulty IAC valve can cause the idle speed to be too high. It may be sticking open, allowing too much air in, or conversely, not opening enough causing the engine to compensate by increasing the fuel, creating a rich condition.
* Vacuum Leaks: Leaks in the intake manifold or vacuum lines can cause the engine to run lean (less fuel), but the ECM might compensate by adding extra fuel, resulting in a rich condition. A high idle could also be a symptom if it's causing incorrect readings of manifold pressure.
* ECM Issues: Although less common, a problem with the engine control module itself can lead to incorrect fuel delivery and idle control. This is usually only diagnosed after checking all other components.
* Fuel Pressure Regulator: A faulty fuel pressure regulator could maintain excessively high fuel pressure, leading to a rich condition.
* Oxygen Sensor (O2 Sensor): A slow or faulty O2 sensor might not provide accurate feedback to the ECM about the air/fuel mixture, resulting in the ECM continuing to deliver a rich mixture even when it's not needed.
Troubleshooting Steps (in approximate order of ease):
1. Check for Vacuum Leaks: Visually inspect all vacuum lines and the intake manifold for cracks or loose connections. Use a vacuum gauge to test for leaks if you suspect them.
2. Clean the MAF Sensor: Carefully clean the MAF sensor with MAF sensor cleaner (following the cleaner's instructions precisely). Do not touch the sensor element with your fingers.
3. Clean the IAC Valve: Remove the IAC valve and clean it with carburetor cleaner or electronic contact cleaner.
4. Check TPS Voltage: Use a multimeter to check the TPS voltage at idle and at various throttle positions to ensure it's within specifications (consult your repair manual).
5. Check Fuel Pressure: Test the fuel pressure to see if it's within the manufacturer's specifications.
6. Check O2 Sensor: While testing an O2 sensor requires specialized equipment, a failing sensor can often be identified by its slow response time or erratic output voltage.
Important Note: Before undertaking any repairs, consult a repair manual specific to your 1992 Camaro 3.1L V6. This will provide you with diagrams, specifications, and troubleshooting procedures. Attempting repairs without proper knowledge could worsen the problem. If you're not comfortable working on your car yourself, take it to a qualified mechanic.
