* Wiring Harness Issues: A frayed, corroded, or damaged wire in the main harness, especially around the ignition system, can cause intermittent power loss. Focus on the wiring to and from the components you've already replaced. Look for chafing against the engine block or other components.
* Ignition Switch: While less common than other components, a failing ignition switch can interrupt power to the engine. This is a tricky diagnosis as it doesn't always throw codes.
* Neutral Safety Switch: This switch prevents the car from starting unless it's in Park or Neutral. A faulty switch can cause intermittent starting problems.
* Battery Cables and Connections: Poor connections at the battery terminals or corrosion on the cables can cause intermittent power loss. Clean and tighten these connections thoroughly.
* Alternator: While the alternator charges the battery, a failing alternator might not provide enough power under load (e.g., while driving), leading to the engine dying. Test the alternator's output voltage under load.
* ECM (Engine Control Module): Although you state no codes, an intermittent ECM failure is possible, though less likely given the other components replaced. Sometimes a faulty ECM might not trigger a code. A professional scan might reveal something missed by a basic code reader.
Troubleshooting Steps:
1. Visual Inspection: Carefully examine all wiring related to the ignition system, fuel system, and crank sensor. Look for any obvious damage, corrosion, or loose connections. Pay close attention to the area near the steering column (ignition switch) and where the harness passes close to hot engine components.
2. Voltage Testing: Check the voltage at the battery terminals while the engine is running and at various points in the ignition system to rule out voltage drops.
3. Professional Scan: Even without codes, a professional-level scan tool might pick up subtle issues the basic code reader misses. This is especially important if you suspect the ECM.
4. Check the Fuel Pressure: Ensure the fuel pressure is consistent and within specifications, even after replacing the pump. A weak fuel pressure regulator could be the culprit.
5. Ignition Coil (if applicable): While you replaced the ignition module, the ignition coil itself can also fail. Consider testing or replacing this as well.
Remember safety first! Disconnect the battery negative terminal before performing any electrical work. If you're not comfortable with automotive electrical work, it's best to take your vehicle to a qualified mechanic for diagnosis and repair.
