2004 Chevy Cavalier 2004 Cavalier

I have a 2004 cavalier, after it warms up and between the speeds of 40 and 50 mph it acts like its trying to downshift or kick into passing gear but you can hardly tell it. Its very minor and at the same time this started the cruz control stop working. The transmission shifts great and the motor runs great. It does not do it all the time. Thank you so much for your help