X5 E53 Warning Fuel Inject. System 3.0D 2004

[No Longer]

Have this error showing, Starts runs fine, when kick down revs go up error pops up on dash, no increase in speed just higher revs - almost as if it has gone into safe mode.

No doubt in for a bill, can anybody advise possible cause(s)and after market solutions in the north herts/south beds area (Luton) or is it a main agent job?

Thanks