Good to hear you got the reason. There is always possibility of a fault we all can't include with normal thinking.
In super charged applications that use an FMU the same action is done to raise fuel pressure to feed the exta power.
Now your all set to fix the rest of the problems and end up an expert on the system.

 

DONE! (well sort of)
The FPR is not fixable, so a new one went on.
Everything is great - for a few hours – then the same damn problem comes back.
Fuel pressure is getting weaker as we test, and it wants to stall at over 30% throttle again..
We’re getting symptoms like the brand new fuel pump is failing.

But wait! – the gas gauge quit, then started working again all my itself.
The fuel tank connector was just a little loose – the connector clip had broken years ago.
The fuel pump was not getting good voltage.
It’s waaay too late to drop the tank & replace the connector, so we rolled up as much foam rubber as we could fit between the frame & the tank & crammed it on top of the connector.
It was crude – but effective.
Done – (we hope).. THE KOER test only gives a code 33. We'll fix that some other time.

Thanks to all,
-Bill

 

Well - It's back.
Replaced the MAP. It was way out of range but the frequency was going up & down with vacuum and the EEC had some what adapted to it.
TPS, MAP, & fuel pressure now check good per Haynes.
It starts & idles OK, not great, but OK.
As you open the throttle it goes way lean & wants to stall.
If I pull off the MAP hose, it of course goes way rich, but it will take throttle & rev almost normally.
I keep comming back to the TPS, like maybe a bad spot at part throttle, but the voltage sweep is perfectly linear from 1 to 4.5 volts.

At this point I'm guessing the EEC has a problem, like maybe part of the speed/density map got corrupted.
A new computer is on order.

 

I feel like the frog that got cooked as the heat went up to slowly to notice.

The fuel pressure has fallen off since I last checked it.
20 PSI won't get it done.
-Bill