Here's a breakdown of likely culprits and troubleshooting steps:
High-Probability Electrical Issues:
* Alternator: A failing alternator won't properly charge the battery. As the battery voltage drops, the engine's computer (ECM) and other electrical components may malfunction, leading to hesitation, stalling, and erratic clock behavior. Get the alternator tested at an auto parts store – they usually do this for free.
* Battery Cables and Connections: Corroded or loose battery terminals can cause intermittent power loss, leading to the symptoms you describe. Clean and tighten all battery connections.
* Wiring Harness: Age and heat can cause wires to fray or short within the engine compartment's wiring harness. This is especially true in a 30+ year old vehicle. A visual inspection for damaged wiring is crucial. Look for melted insulation, broken wires, or signs of corrosion.
* Ignition System: A failing ignition coil, distributor cap, rotor, or even ignition switch could cause intermittent misfires and stalling. These components are more likely to fail when hot.
* ECM (Engine Control Module): While less likely, a failing ECM can cause a wide range of problems, including those you describe. This is generally a more expensive repair, and testing requires specialized equipment.
Less Likely (But Possible) Issues:
* Temperature Sensor: A faulty coolant temperature sensor could send incorrect information to the ECM, leading to poor fuel mixture and stalling. However, this is less likely to cause the clock to malfunction.
* Fuel Pump Relay: While related to fuel delivery, a failing relay is an electrical issue.
Troubleshooting Steps:
1. Battery and Alternator Test: This is the *absolute first step*. Get your battery and alternator tested at an auto parts store.
2. Visual Inspection of Wiring: Carefully examine all wiring, especially in the engine compartment, for damage.
3. Clean Battery Terminals: Thoroughly clean and tighten the battery terminals and cable connections.
4. Check for Trouble Codes: If your Lumina has a check engine light (CEL), get the trouble codes read using an OBD-I scanner (you'll need one specifically for older vehicles). This can pinpoint the problem area.
5. Ignition System Inspection: Inspect the distributor cap, rotor, and ignition coil for cracks, wear, or damage.
Important Note: The fact that you've replaced the O2 sensor and other parts suggests the original diagnosis might have been incorrect. Electrical problems are often misdiagnosed because they can manifest in many different ways. Start with the simplest and most common electrical checks first. If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic. A good mechanic can use diagnostic tools to pinpoint the problem more efficiently.
