hm. an over-heated piston could very well be a culprit. ..... thanks for the heads up on that! If i dont find anything under the valve cover, that'll be my next step.
as for unplugging the spark plug, I already did that, as stated in the OP. Both Spark and fuel were pulled from #4 and the sound still remained.
as for unplugging the spark plug, I already did that, as stated in the OP. Both Spark and fuel were pulled from #4 and the sound still remained.