Oil contamination from a leaking cam cover gasket.
It gets onto the plug tops and shorts them out.
cure is new gaskets and possibly coil/extension.
Open the cam cover to the coil over and have a look.
1/4 drive
November 2011
Partially clogged injector, coil pack not mating cleanly with sparkplug, dodgy/worn sparkplug, low compression, loose/intermittant connections to coil packs/injectors, poor signals from lambda sensor. The last one should in theory of generated a fault code on the diagnostics but the others would'nt unless it caused a big enough missfire to be picked up by the "Knock sensor" and then that would generate a code.
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