loses speed at 60 and needs extra push on gas to regain?

What is your question?

Driving on by pass at a speed of 65, out of the blue, loses speed. Takes a few seconds to push on gas to get it to go back up. Then when stop at light, it takes several seconds for it to speed up enough to change gears. Does this for next several stops, but then runs fine again at 65. Eventually stops and may not occur again for several days, but then, may occur again the next day.

What makes this problem better or worse?

Do not know.

How long has your 2004 Chevrolet Venture had this problem?

a few months ago and now back again, more frequent.