Despite using a stop-leak solution, the rough idle could persist due to several reasons:
1. Limited effectiveness: Stop-leak products may not always provide a permanent fix for a blown head gasket. While they can temporarily seal minor leaks, they might not be able to withstand the pressure and temperature demands of a combustion engine for the long term.
2. Further Gasket Damage: Using a stop-leak product may have exacerbated the damage to the head gasket, leading to a larger or more complex leak that cannot be effectively sealed by the stop-leak solution.
3. Other Factors: Misfiring in all cylinders suggests that the problem goes beyond the head gasket leak. There might be ignition system issues, fuel injector concerns, or other mechanical faults contributing to the rough idle.
Recommendations:
- Consider getting a professional diagnosis to identify the precise cause of the rough idle and misfiring.
- It is generally not advisable to rely solely on stop-leak products for a permanent repair of a blown head gasket. They should be viewed as a temporary measure at best and should not replace a proper mechanical repair.
- A blown head gasket can cause significant engine damage if left unaddressed. Consider having the head gasket replaced or the engine overhauled to prevent further issues and ensure optimal engine performance.
