The only thing I can think of is bad rings or valves in those cylinders. Do the heat ranges on all the plugs match? if some are too cold, the excess soot wont get burned off. Thats the only thing I can think of.
Jonathan S. Keffer
Certified Yeti Trainer
Richard Roy Schlicht-
Good Grandfather, Veteran Wrench Turner...
"If it ain't broke, fix it 'till it is..."
Es gibt nichts, zu befürchten, aber befürchtet sich.
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