Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
Sounds like a failing in-tank pump.
Becoming very common now.
Which engine do you have, 4JH1 or 4JJ1?
Isuzu may different to Holden, Holden does have an intank pump.
Here is some info regarding checking for air leaks:
If has a Holden badge, it has an intank pump.
I believe the Isuzu version also does.
If it put the engine light on, the DTC that set should be diagnosed.
My bet is low fuel rail pressure.
There is a revised Suction control valve (for Holden only) on the back of the HP pump.