i have a 2002 polaris scrambler 90 and it's missing and stalling out to where is would barly move, sometimes i have a hard time getting it to start. what would could this? it has a new plug.. could this be the CDI box that isnt working right? if anyone could help it would very much be helpful..thank you

 

First things first,since you've changed the plug,might help to clean the carb next if you haven't already done so. Engines have to have air, good fuel, good compression and spark to run properly.