Help - 1986 5000cstq Suddenly Running Very Poorly

[Eric_R_Kissell@email.whirlpool.com]

The 1986 5000cstq did not run well Thursday afternoon when I left work.

It ran fine this morning driving into work.

Seems to me that it is suddenly running really lean. 

Symptoms after work: Started fine. Idled a little rough. Missed terribly 
upon attempting to drive away. Almost died out then surged. Did not have 
much ability to move itself. Stumbled with occasional knocking, even on 
relatively low-effort acceleration. Ran a little better once warm, but 
still not much power and stumbling with occasional knocking if pushed 
harder than it liked, which was not very hard at all. I had to be really 
gentle with it. There were no large hills on the trip home, but had there 
been any hills it seemed that it would have caused terrible knocking and 
stumbling. Was able to slowly work up into higher rpms (>4000) when taken 
up gently enough. Boost gauge on dash shows pretty normal amounts of boost 
for rpm. 

Got home and pulled codes - 4444 - Nada.

Cannot find any obvious hose leaks.

Again, it seems really lean to me. 

Where should I start looking? 
Fuel pressure? 
Vacuum hoses? 
Some sensor? 
Fuel pump (less than 3 months old)?
Where?

What could work fine driving into work and then act so wrong on my trip 
home 9 hours later?

I will greatly appreciate any help, BTDT, etc. 

TIA,
Eric R. Kissell
1986 5000cstq, 1.8 bar, k24, not happy right now