After sitting for 3 days my '97 Dodge Grand Caravan SE, 3.3 l. engine, won't start. For months it has occasionally cut out while driving, but has restarted easily. In recent weeks the engine has been running rough. The battery is new and the starter turns the engine vigorously. In one of my attempts to start it the engine ran roughly for 3 seconds, indicating a marginal condition. The fuel line re-pressurizes with each attempt to start, squirting fuel out of the valve when it is pressed, indicating that the fuel pump is working. It was replaced 4 years ago. I think the problem must be electrical, in the ignition system. How should I proceed to fix it? I need to move it before street-sweeping on Friday morning.