rough/stalling at idle

[Fat G]

I have a '98 Outback. When I finished for the season everything was running smooth. I had it winterized and dewinterized and now it is stalling out when I am in neutral. Before I put in this weekend I changed the fuel filter/water separator. (not too much crud and no water). I also filled it (3/4 tank) with 89 fuel and an octane booster. Since I live three hours from my boat I'd rather see if there is something I can do before taking it to the shop. Any suggestions? I'm thinking something in the way of fuel but I'm far from a mechanic!

[JesseC]

When was the last time you changed the cap and rotor? They get nasty quicker than they do in an automobile. How old are the plugs?

[Fat G]

I haven't and am not sure when the last owner did. I'll put that on my list of things to do when I get back. Let me know if you think of anything else.