rangerover l322

question for someone my l322 keeps throwing up injection fault on dashboard its had new low pressure pumps new pressure control valve on high pressure pump. but still lots of air in the pipes and just stops and takes a bit to restart

Is it down on power?

Funnily just watched this last night.

it does lose power then it comes back but if you accelerate hard its like you turned it off

You wrote low pressure pumps...plural....so did you change both...the one in the tank and the one on the side of the tank?

yes both of them and the pressure switch on the high pressure pump it went fine for about 400 miles and now its starting with a struggle but wont drive far and if you give it throttle it dies and comes up with injection system fault on dashboard
the fuel line is clear plastic and its full of air almost like its run out of diesel but it has over half a tank

TD6 by any chance

Have a leak off test done to rule out injectors before spending any more money on parts.

Filters? A friend had his serviced by Main Stealers and the fitter/ spanner monkey/whoever wasn't brushing the tiled floor left the old fuel filter seal in place when he/she fitted a new filter so ended up with two which let in air.

I’ve seen oil filters like ^^^. Old one gets put on dry and some numpty says ‘that’l do’.

As @Mark Piercy points out....do a leak off test and see if any injectors are leaking back excessively first. Cheap and simple to do.