V70 D5 - strange fuel issues
 

Hi there,

I've been having some very strange issues with my 2003 V70 Euro 3 D5244T. It started slowly, occasionally going into limp mode during long drives and progressed to cutting out every 30 seconds or so.
The main (and weirdest part) is that once started, it will idle indefinitely. It'll happily pull itself around on the clutch. If I accelerate fairly hard and keep the revs above 2k it will drive mostly fine - but as soon as I let off the throttle and it dips below 1k, it'll stutter and cut out.​

These are the reoccuring codes:

• P0094 Fuel System Leak Detected Small Leak
• P0088 Fuel Rail/System Pressure - Too High​

Things I've done so far:

I had a similar issue before that turned out to be a clogged fuel filter, so that was my first change - no difference.
I was advised by a local Volvo specialist to replace the tank pump after they found no fuel reaching the injectors. This also made no difference, except now it takes at least a minute to prime the system every time it shuts off!
I suspected a physical blockage so dropped the tank just enough to pull out the fuel feed line between pump and filter, flushed it out but no difference.
Checking the return line of the injectors showed nothing exceptional either.
I even pumped out all the fuel which showed nothing except I must have picked up some bright blue farm diesel from a dodgy petrol station at some point, it was pretty diluted though.

I have a theory that it might be pulling air into the line somewhere, but not a clue how to diagnose? It seems to pull fuel fine with the injection pump working hard, but as soon as demand drops it can't seem to keep the flow up.

Has anyone dealt with anything similar before? It's baffled me and the specialist I've been taking it to for years. Any advice appreciated, thanks!

Do you do mostly short trips? If you do it basically has to regenerate each time you drive as not only does short trips cause more build up on the DPF but it also limits how much it can regenerate.