A Navy attack plane with engine trouble crashed and burned in a residential area, injuring three people in two houses as the pilot bailed out safely and landed in a tree, authorities said.

Several rounds of ammunition aboard the single-engine A7 Corsair II exploded in the fire, said Navy spokesman Nick Young. Lt. (jg) Scott S. Scheurich, 25, was flying from Roosevelt Roads Naval Air Station in Puerto Rico and about to land at Cecil Field when the craft developed engine trouble shortly after 10 a.m. EST, Young said.

Young said the pilot tried to steer the plane away from a populated area, but as the plane's altitude dropped below 1,000 feet, Scheurich ejected. The aircraft slammed into a subdivision about 20 miles south of Jacksonville, leveling one home and coming to rest in front of another house after sliding about 100 yards. Teen Pregnancy Program --

NEW YORK--The Ford Foundation announced it will spend another $1 million the next two years on grants to programs designed to reduce teen-age pregnancy.

Foundation president Franklin A. Thomas said the $1 million brings to $2.5 million the foundation's spending on teen pregnancy prevention for 1982-83.

The money will go to community programs in New York, Boston, Phoenix, Baltimore and Riverside, Calif.