take it to man they will plug it in think it called a leak off test couple of hours to sort it tops youll have no change out of around £750 ish bring it out of man take it back to your yard maybe if your lucky a few days and hey presto it comes back on and then go to your tool box get the biggest spanner you can and sling it at the dam thing .if your lucky they may get it right first time but as what everyone else says I don’t think so ,you could try changing the fuel filter and pre filter out first but that’s pot luck .I was speaking to a fitter over Liverpool way who looks after a lot of the tga s and he said through experience he ignores the injectors and strips the pump and that’s where he starts the fault finding first and has a lot of success clearing the fault