Also check the lift
pump filter. A much over looked filter. If there is one fitted that is. It is a light gauze and IMO is not required, providing you have good filters ecverwhere else. The pump filter is a pain to get at in an emergency
and I remove them before the "emergency" arrises.
To the stopping situation, you need to be a little more accurate than "9'ish". Firstly, you need to ensure the RPM
is correct to the indicator. If it is an electric
meter that is. It will have a control for calibration on the back. Ensure it is correct. The difference of only a few RPM could be your problem.
Check the stop cable is fully home when running. If it is pulled slightly tight, it could be enough.
As Pat stated, at nearly 1000hrs, it would be a good point to have injectors serviced and as you have such a problem, I would suggest having the pump checked and calibrated at the same time. The pumps have springs internally that can change resistance with heat and sometimes break. Plus they have wearing parts
and a calibration maybe required.