If your Alfa Romeo (especially those with Twin Spark, JTS, or even modern MultiAir engines) has started to stutter, idle roughly, or lose power under acceleration, you are likely experiencing an engine misfire. Often, this is accompanied by a flashing Check Engine light and a P0300-series OBD2 error code.
When this happens, the first reaction of many owners and mechanics is to order a brand new set of spark plugs and expensive ignition coils. But before you spend hundreds of dollars on ignition parts, there is a simple, free check you must do—and it might reveal that your real problem is just a failing valve cover gasket.
The “Wet Coil” Discovery
To find the true cause of your misfire, pop the hood, remove the engine cover, and carefully pull out one of your ignition coils.
Look at the rubber boot of the coil and the spark plug sitting down inside the engine cylinder head. Are they swimming in fresh, golden, or dark engine oil? If the answer is yes, you have found your misfire.
The oil pooling in the spark plug well creates a barrier that prevents the ignition coil from sending a strong electrical spark to the plug. Instead, the electricity arcs into the oil or the cylinder head, causing the cylinder to completely miss its combustion cycle. This is what causes your engine to shake and lose power.
How Did Oil Get in the Spark Plug Well?
Your engine’s camshafts and valves are housed under the valve cover (also known as the rocker cover or cam cover), which is constantly sprayed with pressurized oil. To keep this oil sealed inside the engine, a rubber valve cover gasket sits between the cover and the engine block.
Crucially, this gasket doesn’t just seal the outside perimeter of the engine. It also features inner circular seals (spark plug tube seals) that keep oil out of the deep wells where the spark plugs live.
Over time, due to the intense heat radiating from the engine block, these rubber tube seals bake, turn brittle like hard plastic, and crack. Once they lose their elasticity, oil easily bypasses them and fills up the spark plug tubes.
The Fix: Don’t Treat the Symptom, Cure the Disease
Many people simply wipe the oil off the coils, clean the spark plugs, and put everything back together. While this might stop the misfire for a few days, the oil will inevitably leak back into the well, and the misfire will return. Furthermore, prolonged exposure to hot engine oil will eventually destroy the rubber boots of your expensive ignition coils.
The only permanent fix is to remove the valve cover and replace the hardened valve cover gasket and spark plug tube seals.
(Planning to do it yourself or show your mechanic? Look at our exploded view diagram below to see exactly where the perimeter gasket and the inner spark plug seals are located).
Choose Your Replacement Wisely
Replacing a valve cover gasket requires removing coils, wiring harnesses, and unbolting the cover itself. It’s not a job you want to do twice. Cheap aftermarket gaskets often fail to withstand the high temperatures of an Alfa Romeo engine, meaning you’ll be back to cleaning oil out of your spark plugs in a matter of months.
Protect your engine and your ignition coils by using a premium, high-temperature replacement gasket designed for an exact, leak-proof fit.