The check engine light does not come on so I haven't checked for codes. The engine will misfire but only after it has been running rough for a while and is fully warm. It acts like it is getting too much or not enough fuel. When I look into the throttle body it seems to be getting plenty so I'm guessing it is getting too much.
Since it went from running great to running bad all at once, it seems unlikely that it is worn tune up parts, but I will check to see when they were replaced and will check them out. Since it gets better when I restart the engine, even when it is warm, it seems unlikely that it is the pick up in the distributer. If you have any more ideas, let me know, otherwise I'll get back to you after I check these things out.