There is no fault codes!only the message engine malfunction service now. When you turn engine off message disappears. Only appears when you start the engine and it runs ruff won't go over 2000 rpm so can get into 3rd gear. So I don't know were to start?First you need to have the fault codes read and report back.
I brought code reader no faults found. Took it to a garage it's no1 injector going to be charged over £600 .Get a garage with a code reader to read or buy your own code reader and plug it into the OBD2 port and see what codes are stored. Take note of the error code numbers and go from there.