Help needed

Hey guys, I’ve had my ST180 5 years and I love her! However these past few months there is an issue and it’s been to 3 garages and I’ve done what’s needed yet still have this issue!! Please has anyone had this before? 
 

so let me fill you in 

car is 10 years old had cambelt done by my trusted garage, they said the old belt was done before I had it and was tipexed and done bad. When I collected she was revving by herself so they did 2 smoke tests which she passed and checked timing. All ok. They then said it may of been mapped and now timing is correct it’s not happy. 
so I took her to a performance garage who had her all day no revving then when I collected she was revving, they then took off timing belt to check and all done perfectly, so not that! By then EML was on he said 02 sensor so was changed, also did another smoke test, and passed, driving lovely, 3 days later did it again! 
then it went to a Ford specialist, they did a full diagnosis on her and another smoke test as hunting usually means air leak, she passed again, he then said he plugged in and said it my pre cat sensor which I’ve now done, he also checked BHP and she hasn’t been mapped! now revving is better but when hot she just climbs by herself to 2 Rev then drops and I’m now fed up! 
has anyone had this issue? If so what did you do? She is driving a bit better but still feels hesitant to me.