[BTKenney]

The car will unpredictably stall. Exhaust is too rich, will not pass CA-Smog.
Replaced Air Management Valve, O2 sensor, Air pump, distributor and spark plugs.
Considering replacing Fuel Injectors. Cadillac mechanics are unsure new injectors will
Solve issues. What do you think? Any ideas?

 

[Ranger]

If it is fuel injected and running rich, you might check the FPR.

 

[BTKenney]

Any recommendations on fuel injectors for a
1990 STS. 4.5 liter V8, PFI system to replace original Equipment ?

 

[basscatt]

Any recommendations on fuel injectors for a
1990 STS. 4.5 liter V8, PFI system to replace original Equipment ?

==============================
DIAGNOSE the problem - BEFORE throwing a bunch of parts at it -

spend a few minutes and check a couple things out -

as Ranger suggested -
inspect the FPR - Fuel Pressure Regulator -
pull the vacuum supply hose and inspect it for ANY sign of gasoline -

check the fuel pump pressure at the fuel rail -

with the engine running - use a stethoscope - or similar -
and LISTEN to each injector -
you should hear a distinctive click each time the injector "fires" -

OHM out each injector -
you are measuring the electronic resistance of each one -
they should all be about the same -

 

[BTKenney]

Great Advice. I learned some new things here and I appreciate it!