However, some common culprits for rough idling and a check engine light in vehicles of that era include:
* Mass Airflow Sensor (MAF) or Air Flow Meter (AFM): A dirty or failing MAF/AFM sensor provides inaccurate air/fuel mixture information to the engine computer, leading to a rough idle.
* Throttle Position Sensor (TPS): A faulty TPS sends incorrect information about the throttle position, again causing poor fuel mixture and idling problems.
* Idle Air Control Valve (IACV): This valve controls airflow at idle. A clogged or faulty IACV can prevent the engine from idling smoothly.
* Crank Position Sensor (CKP): This sensor tells the computer the position of the crankshaft, vital for ignition timing. A bad CKP will result in misfires and rough running.
* Cam Position Sensor (CMP): Similar to the CKP, but for the camshaft. Problems here cause similar issues.
* Ignition System Problems: Worn spark plugs, faulty ignition wires, a failing distributor cap or rotor, or a weak coil can all contribute to misfires and rough running.
* Vacuum Leaks: Leaks in the intake manifold or vacuum hoses can disrupt the air/fuel mixture.
* Fuel System Issues: A clogged fuel filter, low fuel pressure, or failing fuel injectors can cause poor fuel delivery.
* Oxygen Sensor (O2 Sensor): A bad O2 sensor can lead to incorrect fuel mixture adjustments, affecting idle and potentially triggering the check engine light.
What to do:
1. Get the diagnostic trouble codes (DTCs): This is the most important step. You'll need a scanner compatible with your vehicle's OBD-I system. Auto parts stores often have scanners that can read these codes, or a mechanic can do it for you.
2. Check the obvious: Inspect the engine bay for any loose vacuum hoses, damaged wiring, or obvious signs of problems.
3. Visually inspect: Look at the spark plugs, wires, distributor cap, and rotor for wear or damage.
4. Clean or replace: Start by cleaning the MAF sensor (if it's accessible and you're comfortable doing so), the throttle body, and the IACV. Replacing worn parts is usually the next step after cleaning.
Without the DTCs, any further troubleshooting is purely speculative. The codes will point you in the right direction for a proper diagnosis and repair. If you're not comfortable working on your vehicle, take it to a qualified mechanic.
