AAZ Injection pump low idle when restarting the car hot

[WeekendMechanic]

So this is a later AAZ pump with the vacuum idle and electronic advance retard NOx pollution solenoid.
I've adjusted the idle lever manually to rev an extra 350rpm to 1150 rpm all so increased fuel enrichment from the fuel screw to compensate this drop as well.
But no matter how much I adjust the idle whether high or low. after long trips the idle drops to 750rpm even with ac vacuum on which makes it want to stall under load its as if its pre set to this rpm can it be adjusted with vcds?
Car is a 97 Golf GTD.

[WeekendMechanic]

People lets brain storm,what would be things inside the pump that would cause an idle drop when hot?

[ORCoaster]

No Experience with that IP,  Saving my two brain cells any trauma. 

[WeekendMechanic]

Its this pump
I have two questions..
Would too low a pressure or too high a pressure inside the pump cause the governor to not keep its default position Iv checked the pressure relief valve and its fine?
What would be the pressures of the return and intake when hot?
This is the way I got it from the shop from a rebuild it was working fine before, to be honest I don't want to take it back and just do it myself.

[srgtlord]

So I had a similar problem on an old pump. It turned out the "OUT" bolt was clogged solid

[WeekendMechanic]

So I had a similar problem on an old pump. It turned out the "OUT" bolt was clogged solid

Thanks.
So I checked, no clogs...
A note, this pump has never run on veg oil.

[WeekendMechanic]

I give up...
One question I'm going to buy a new pump, I know they greased them up on assembly, but how long can they remain in storage before they go bad, I'm asking cause its an old pump and i don't know how long the shop has had it for, please the listing was uploaded 3 years ago.

[WeekendMechanic]

So I installed the new pump and the difference is night and day.

So smooth it's like butter, even with the A/c on, no stalling, it eats it for breakfast, parking and uphill power is always available.

So now I've got a spare pump that stalls at low rpm, I haven't cracked it open yet, but does anyone know what to look for first?

[ORCoaster]

The first thing you look for is a place to dig a deep hole and bury that bad boy.  Think of it no more, you're all set with the new pump.  Don't look back. 

[fatmobile]

I'd check the governor springs.
the ones captured/caged coming from the lever.