My 2005 Volvo s60 sometimes stalls at stop lights. It is an intermittent problem. Some sensors have been replaced. The oil pan has been replaced. I added drygas and “seafoam” to a full tank of gas twice. The spark plugs and wires are replaced. And a few other repairs were guessed at. The problem persists. It’s fine on the highway. It’s only in traffic on city streets that it stalls but not right away. Usually it’s after about 20 minutes of city driving that it happens. The check engine light doesn’t go on. When it happens, I put the car in Neutral and it starts right up again. Can you help? I know more repairs were made to try and fix it but I can’t remember what they were sorry.
This is a challenging issue, especially given its intermittent nature and the fact that the check engine light isn’t illuminating. Based on the information you’ve provided, here are some potential causes and suggestions:
1. Idle Air Control (IAC) valve: This regulates idle speed and can cause stalling if faulty. Since the problem occurs after some city driving, the IAC valve might be heat-sensitive.
2. Mass Airflow Sensor (MAF): If not already replaced, a faulty MAF can cause stalling issues, especially at idle.
3. Fuel pump: A weak fuel pump might struggle to maintain proper pressure during extended idle periods.
4. Vacuum leak: A small leak that worsens as the engine heats up could cause stalling.
5. EGR valve: A stuck EGR valve can cause stalling, particularly at idle.
6. Throttle position sensor: If faulty, it can send incorrect signals to the engine control unit.
7. Crankshaft position sensor: This can cause intermittent stalling if it’s beginning to fail.
8. Alternator: A failing alternator might not provide enough power to run all systems after extended use.
9. Fuel injectors: Clogged or failing injectors can cause stalling, especially at idle.
10. ECU issues: In rare cases, the engine control unit itself might be malfunctioning.
Given the intermittent nature and the specific conditions under which it occurs, I would suggest:
1. Use a scanner that can log data while driving. This might catch irregularities even when the check engine light isn’t on.
2. Perform a thorough vacuum leak test, especially when the engine is warm.
3. Check fuel pressure, particularly after the car has been running for a while.
4. Inspect all electrical connections, as heat can exacerbate loose connections.
5. Consider having the alternator tested under load.
If you’ve already addressed these issues or would like more specific advice, please provide more details about the additional repairs you’ve had done. Also, consulting with a Volvo specialist might be beneficial, as they may be familiar with model-specific issues.
