1991 Nissan Skyline 6 cyl Two Wheel Drive Manual 135000 miles
rb20 det engine has ran spot on for three years suddenly took two attempts to start rather than the usual first turn of key then once running all seems ok until rpm is increased to 15000rpm you get an engine knock if the revs are held steady the knock dissappears so basically any sudden increase or decrease in revs and you get a knock. I suspected insufficient spark might be causing erratic combustion so removed coilpacks and plugs where I discovered the carbon tips on at least four of the six coils were very ragged indeed. Im in the process of purchaseing some new plugs and coils mainly because they are deffinately showing a good sign of needing such. Now then my question is could the faulty coils be the sole cause of the knocking symptom afore mentioned. And should I think of looking in the direction of crank and knock sensors. Thank you would appreciate good helpful food for thought answer cheers.