and while I'm on the subject of Spark Plugs !

SHOULD YOU REPLACE YOUR SPARK PLUGS?
One of the leading causes of hard starting is fouled or worn spark plugs. When a fuel injected engine that normally starts quite easily has to be coaxed to life, it often means the plugs are overdue for a change. As the electrodes wear, the voltage required to jump the gap and ignite the fuel mixture goes up. At the same time, accumulated deposits on the insulator can drain off voltage before it even has a chance to form a spark. So the engine fails to start or starts only reluctantly after prolonged cranking.
Spark plug sales take off when cold weather arrives is because many motorists put off changing the plugs until they absolutely have to. The vehicle manufacturer's recommendations to change the plugs every 30,000 miles for preventative maintenance are ignored, so the plugs continue to rack up mile after mile until they've deteriorated to the point where they're causing noticeable driveability problems.
Emission checks will catch a lot of bad plugs and force motorists to change plugs that need to be replaced. But in areas where emission checks are not required, the only incentives for changing the plugs are the driveability problems created by the plugs themselves. So many motorists today think they're saving money on maintenance by putting off a plug change until it's obvious the engine needs new plugs. Then and only then will they begrudgingly spend any money on a new set of plugs.
WHY CHANGE 'EM?
What motorists need to be told today is why the plugs should be replaced according to their vehicle manufacturer's scheduled maintenance recommendations be it every 30,000 miles, or 60,000 to 100,000 miles in the case of long life plugs. So why not visit the Auto tap website for three good reasons why the plugs need to be changed: ( cos I don't wanna copyright infringe by pasting them here - sorry)

Ho Hum......how incredibly boring the Easters seem to get.............I never seem to have any money to do anything or the energy to take up the various 'free' ways of enjoying oneself in this great capital city. Working at the Local council is , i imagine like being in a coma. A big new change in the Parking regulations is imminent and our office is struggling to even get the existing IT to work half way decently. The on -going saga with the Harley - for which I have lost all motivation, was kick started(pun intended) when, after the problems on the tin box proved to be no more than a set of HT leads, I figured the symptoms were identical in the problems I was having with the bike. After several visits to bykuz.com I found a quote for the Voltage reg at £95-100 which scared the bejeepers out of me. So at the 11th hour having just stalled at pressing the order now button for a £120 voltage regulator I figured I'd replace the Spark plugs and leads first (intended replacement anyhow) before splashing out on the regulator.....yeeh hah ! saved myself £120 ! runs like a dream. anyway back to the office of coma hQ. later.