why is car slipping out of gear (stick stays in place) in 5th gear.

What is your question?

driving about 55mph..accelerating to pass or increase to speed limit, car will slip from 5th into neutral.can hear engine rev; car does not get power though. stick stays in place. lasts a second or so, then will go back into gear. & rattling/clunking noise also. just started-but have had problems in 1st gear b4/jerking when accelerating from a stop. 5 speed.