our 03 has been hard to start the last 2 months. showed the fan clutch code on the odometer, everything checked out fine, but it takes about 10X over before it will fire and when it does, it sounds really weak. its had a large pressure box on it since it was new, changed filters very recently several times, but no change. sometimes lopes at an idle, but still runs and pulls strong. its got about 170,000 on it now. any ideas???