Losing Power

Can anyone help, I have a Nissan Micra K12 1.2 SE 2004 petrol manual model, have had her since brand new.
I am driving and cannot go any faster than 30-35 miles per hour in any gear? Then the next day I start her up and drive normally, this has happened on and off now repeatedly for 2 months. So I took her to my Nissan dealership, they could not find anything wrong, they connected her to the diagnostics, and there were no fault codes? What on earth can be wrong, can anyone please make any suggestions, will be highly appreciated, thank you.
 
Back
Top