Craig,

It could be a defective check valve on the fuel pump. This would allow the fuel line pressure to drop over a long shut down period and require a lot of cranking to get the lines re-pressurized. After a short shut down it could retain pressure long enough to produce a fast start. To check the valve ...let the brick sit over night, crack the fuel line connection at the fuel rail open slightly and see if there's pressurized gas in the line. If not the check valve may need replacing. It's the small brass piece connected to the fuel pump. Rough idle is not something I would associate with a check valve problem. Maybe it's an unrelated throttle body issue. Have you cleaned yours lately. It's a good idea to do so if you haven't recently. You might check your Throttle Position Switch and make sure it's set properly. What ever the problem good luck sorting it out. Hope this helps.