Hi all. I’ve just bought a 64 plate st 2 and amongst other issues, when accelerating fairly hard and getting up to around 4.5 thousand revs, it drops power fairly drastically and then the turbo gauge will not go over the quarter mark. The engine management light has been coming on.

i took it back as its under warranty and the sales guys called and told me that without the light on he can’t see what the problem is.

i took the car back and drove home. The car did the same thing but the engine management light didn’t come on.

really confused as I know there’s an issue as i took it to a friend who put it on his scanner and it said under boost condition.

id be grateful of some advice 

thanks

Reject the whole car if there are multiple issues and the dealer won't fix them.

It is true that some codes reset after switch-off.  So all you can do is keep ragging it until the light comes back on then drive it straight to the garage.  If the engine management light is on then even basic OBD scanner should pick up the code.  Without the light on there might be a Ford specific code stored, but generic readers won't pick those up.