Thanks for that, actually i jsut thought the same thing as you suggested. So i tried swapping ignition plugs around and hey presto it follows the ignition. So ignition sent back to distributor today, hope to get a replacement fast i hate to be GROUNDED! There dont appear to be any leaks around gaskets other than to the exhaust. My remaining concern is that perhaps the ignition is responsible for the cylinder going out (or not coming on) but the custom exhaust is perhaps responsible for lack of performance. I will return to supplier to find out...