Accelerator / revving issues

[kitty77]

Hi.
I have a 2010 plate megane 1.5 dci .
I have experienced where I am doing say 70mph and the accelerator pedal seems to stick like its gone into cruise control. it sticks for say 10 secs then resumes normal. Made sure It wasn't the mat getting stuck underneath and its not.
More recently as I am moving up the gears into 5th accelerating from 55mph to 58 mph it revs and the rev counter goes up for about 3 secs, its feels like when an automatic is changing up the gears. Any ideas or anyone experienced similar.
Thanks