Engine system fault.

[DannyChelmsford]

So every so often say about couple times a month, I turn my engine on to see engine system fault. with a flashing warning exclamation mark ❗️ 
as I start to drive it’s in limp mode but all of a sudden goes off and the car picks up speed as normal…? 
this also happens very rarely as I’m already driving will come on and I’ll lose power only for a minute later it to go off and pick up speed again. 
However, the last 2 days I haven’t drove it as the engine system fault and red light on the dash has continued to remain and hasn’t gone off like usual. 
the car is in limp mode and when I am static in neutral with the handbrake on my foot to the floor is only getting just shy of 2000RPM..???? 
Any help and advice would really be appreciated and I thank you in advance. 
 

[isetta]

You need to read fault codes using forscan software.