* Loose or corroded connection: A poor connection in the electrical system can cause intermittent faults. This could be anywhere from the sensor itself to the wiring harness leading to the ECM (Engine Control Module). Check all connectors related to sensors and actuators.
* Intermittent sensor failure: Many sensors (like the oxygen sensor, mass airflow sensor, crankshaft position sensor, or throttle position sensor) can give intermittent readings. When they malfunction temporarily, the light might go on, and when they temporarily work correctly, it goes off. These sensors are common culprits in older vehicles.
* Failing ignition system component: Problems with the ignition coil, spark plug wires, or distributor (if applicable) can cause misfires, triggering the check engine light intermittently.
* Exhaust system leak: A leak before the oxygen sensor can cause inaccurate readings, leading to the check engine light.
* EVAP system issue: Problems with the evaporative emission system (fuel tank, hoses, purge valve) can cause intermittent issues and trigger the light.
* Low fuel level: In some cases, a very low fuel level can trigger the light, though this is less likely to be intermittent.
What to do:
1. Get the diagnostic trouble codes (DTCs) read: This is crucial. A scan tool (available at auto parts stores or mechanics) will read the codes stored by the car's computer. These codes pinpoint the likely source of the problem. Don't just erase the codes; get the codes *before* erasing them.
2. Inspect visually: Once you have the codes, check visually for obvious problems like loose wiring, broken vacuum lines, or damaged components.
3. Focus on the sensor indicated by the codes: If the codes point to a specific sensor, that's where you should start your investigation. Often replacing the indicated sensor resolves the issue.
4. Consult a repair manual: A repair manual specific to your 1998 Corvette will provide detailed information about the vehicle's systems and troubleshooting procedures.
Important Note: Ignoring a check engine light is not advisable. Driving with a consistently malfunctioning engine can lead to further damage and potential safety hazards. Even an intermittent problem needs to be addressed to prevent it from becoming a more serious (and expensive) issue.
