Xt660x 2008 not running correctly
 

Hi all, I am pulling my hair out on this one. I have checked the idle speed when at operating temp and is flickering between 1600 and 1400rpm quite quickly - no set pattern. The bike very occasionally was cutting out when in slow moving traffic, thinking about it it seemed to be when I pulled the clutch in hence why I checked the idle speed. Should the idle speed be varying by that much? Also the bike has been parked up for over 2 months and on its last outing when it got warm it started spluttering,missing popping etc as if it was over fuelling or faulty plug. I have ordered a new spark plug as bike has done 5000 miles and I don't believe it has been changed. Now the bike has got a kev mod, laser produro cans and a non standard air filter - not sure on the type or how to check??? I am very interested on fitting a power commander as I seem to think that it will do what the kev mod is designed to do but do it automatically? Is this correct? How would I go about uploading pic of the items fitted to try and establish what has Been fitted and is it easy to remove the kev mod if I needed to to???? Thanks for your time. Max