Update. Got her running and unplugged each injector in turn, #3 made little or no difference. Put a probe into the loom and could see it pulsing but strongly suspect it could be the loom at fault.

Unplugging the MAF while running does make it run worse, if that's possible, so confident that the MAF is doing it's job. If the common rail sensor was faulty wouldn't if affect all 4 cylinders equally?

I'm going to pop 1 and 2 out and swap it with 3 and 4 this morning and see if the fault moves. Plug on the rail sensor is clean and while running gave the plug and loom a wiggle to see if it made a difference but nothing.

Checked the return line and it's clear.

Hi all. Need some help with my long suffering wife's TD4 (04 plate) and it's driving me nuts at the moment and I'm hoping you guys and girls can help. Bit of a long one so stick with it. Picked her up last year with a shot clutch, I knew the vehicle before I bought it and was running fine until...