Fuel filter is the first thing I'd try, it's not injectors, and see if there is any leak that may be drawing in air to the fuel line, check the filter head diaphragm plunger, it should have big resistance to pushing down, if it pushes easy and pops straight back out the diaphragm is split, these are about £15 new, easy to do, and very common failure point, if the plunger comes back out slowly after pushing it is ok.
Also would be worth checking the fuel cut solenoid is nice and free to move, and the solenoid is working ok, ie holding the plunger against the return spring pressure.
tabetha