Hi Tony had the same prob with my 106, chuck in some cleaning additive into the tank (redex or better from checkpoint etc) and give it a good blast but dont speed lol
its prob due to the engine just "plodding" every day but they need a blast now and again to clear them out? a change of spark plugs/oil and filter will help too? if you refer to getting it through mot then make sure you give it a good run before taking it back for retest or the cat wont be hot enough to convert the exhaust gasses thus lowering the emmisions?
hope this helps?
Craig
June 2011