* Misfires: The most immediate consequence of a wrong firing order is misfires. The spark plugs will ignite the air/fuel mixture at the wrong time, disrupting the smooth power strokes of the engine. This leads to rough running, loss of power, and potentially damage to the catalytic converter.
* Increased engine wear: Consistent misfires put extra stress on the engine components. The pistons and connecting rods will work harder, leading to increased wear and tear. This accelerated wear could eventually lead to more serious internal engine damage.
* Damaged catalytic converter: Unburnt fuel and excess heat from misfires can severely damage the catalytic converter. This is an expensive part to replace.
* Potential for valve damage (less likely but possible): In some extreme cases, if the timing is severely off, it's possible for valves to be bent, though this is less common with modern engines and more likely with interference engines.
In short, while a wrong firing order won't instantly destroy the engine, it will cause significant problems and greatly shorten its lifespan if not corrected immediately. It's crucial to ensure the correct firing order is followed when working on the ignition system.
