Poor running when hot; rough idle

The explorer sat for 2 years. The gas was drained and replaced before it was started. We drove it for three days about 250-300 miles. It ran beautifully! The end of the third day, about 7 miles from home at 55mph it lost power. It ran like a slug, the more gas you gave it the more it just seemed to bog down. It was clear down to about 25 mph when smoke started pouring out from under the car. It smelled hot, the smoke was light colored.

It has continued to do this for the past few days. It will hardly get above 25mph before it loses power. It has not smoked since. It starts and runs good before it heats up. It now has developed a very rough idle. We changed the fuel pump, mass airflow sensor, new plugs and wires. It does seem a little better but not much. Wishful thinking probably! The rough idle showed up after we ran a fuel pressure test. The Fuel pressure regulator does not show any fuel in it when you pull the line. The car ran perfectly before we parked it.
Any ideas would really be appreciated. Thank you Gary