waste of time
Temporary bodge lots of insulating tape ( a couple of layers at least ) wound up and down the length of it
As another correspondant suggested, you might as well piss on it.
Remember that, at tickover, the cylinders are probably below atmospheric pressure at the point of ignition, so the spark has an easy line if least resistance through the plug, and the spark is still jumping from the outside of the lead to ground.
When you open the throttle and apply a load to the engine, the cylinders pressure is now probably around 7 - 10 bars above atmospheric pressure, so the previous line of least resistance is now a very difficult path for the spark to jump.
What this means is that, if it jumps occasionally to ground at tickover, it will
jump continually when the engine is under load.
Don't pussy about, replace the lead.
Unless, however, the plugs have over 60,000 miles on them, in which case, replace them first.
Myke
