How is it playing up? Is it that it is not burning properly? Low pressure?
Have you tried useing the proper Coleman Fuel to clean the jets out. I must have had some bad fuel in my Coleman, a fill of the proper Coleman Fuel cured it.
Ok colemans can be occasionally problematic. I always add a little Redex petrol treatment to my fule and this really helps the transfer tube stay clean. Always use clean unleaded fuel and fill up using the filtered funnel colema supply with the stove. Finally make sure you have pumped the stove up with as much pressure as you can to sensure you have got a nice strong clean burning flame.