Sometimes the 954 doesn't start after it has sat for a month or more. It eventually fires up after as many as 10 tries and then it runs perfect from there. It fires up on the first try at any other time. 27k miles. Plugs are 3 years old. Full exhaust, PC III and K&N filter. Everything else is stock engine wise. Battery is 3 years old and on a tender in the winter. I'm no mechanic by any means. What do you guys think.