Lack of Power

[BeenyD40]

On my 2012 D40 I have lost about 50% power when accelerating. It still drops back a gear (auto) when accelerating but not very much acceleration.
I turned off the engine for 5 min and then it ran normal again.
Next Day same problem but I stoped at the shops for 2 hours and the problem was still there when I drove again. I then turned the engine off for 1 min and the problem was gone.
I have looked up similar threads and a lot mention limp mode, how do I know if this is limp mode? I have no extra lights on the dash.
Any Ideas?

 

[Old.Tony]

Sounds to me like a typical dirty/faulty SCV response.

First course of action is fuel system treatment (Liqui Moly is good, $25 from SCA) then remove, clean & reinstall SCV (it's on the fuel pump).

It would be prudent to check other nuisance items like MAFS (rear of the air intake just outside the filter box, remove, spray with electrical contact cleaner, reinstall) and electrical connections (battery terminals usually, sometimes ECU earth).