93 yukon 350 wont stay running at idle

K1500 PICKUP. ? 5.7 TBI. GAS
i will assume eng. compression good and spark good and timed by the book.
it's staving for fuel.!
fuel pressure not at spec,
fuel pressure regulator bad.
injector clogged (injectors screens inside packed)
bad fuel (was bad now bad fuel is in all that path)
MAP sensor bad or clogged up. EGR stuck open
meter mAp pin out,1.5vdc out,keyon to 4.5V WOT (wide open throttle)

we test fuel pressure 3 ways
key pressure
idle
and WOT
the manual covers that, buy the service manual?
so the pressure specs for TBI are at hand./?
there is no fuel rail like MPI so has very odd connections to do pressure tests TBI. (below)
you do know most injectors have 10micron screens inside,and only ultra sonic reverse cleaning cures them right? (or new injectors) I send mine out for pro cleaning, (Usonic)

the hard part of 1995 TBI is getting the TBI specs.
the manuals were 500 pages paper and nobody digitized all page or skipped most the Injection pages.
it is a problem but the used books are sold at EBAY
from GM (real)

rumor has it
"In stock form a tbi operates 11 to 13 psi running a bit higher makes them run better to a point of about 14.5"
the TBI if you look close has a FPR, seen here
it must be good.(diaphragm)
some TBI have 2 injectors, start+idle (and fast run)
as seen here

https://www.rockauto.com/en/catalog/chevrolet,1995,c1500+pickup,5.7l+v8,1031443,fuel+&+air,fuel+injection+pressure+regulator,6124


next up how to read the pressure (tap ports)
I think this is a returnless system (early)
so they make up filter tap point. fuel. or TEE fitting.


https://www.reddit.com/r/MechanicAdvice/comments/10nz5rd/best_way_to_check_fuel_pressure_gm_tbi/

Could be fuel filter,air filter,dirty throttle body.

Sounds like the fuel pump is going bad(or in this case,has gone bad). I suggest that you change the fuel pump and use a fuel cleaner in your gas tank as dirty gas may have caused the problem to begin with.

The spark plug gap may be set to be too great. Pull the plugs, clean them, reset the gap to .038 - .040 " and add octane booster to gas for the first atnk. It may just clear it up. Change air filter also.

CODE 43 IS ELECTRONIC SPARK CONTROL -.KNOCK SENSOR.LOOKS LIKE ALTERNATOR NOT PUTTING OUT ENOUGH VOLTS TO CHARGE BATTERY.YOU NEED 13.5 TO 14.5 VOLTS.CHECK ALTERNATOR FUSE AND ELECTRICAL WIRES.MAKE SURE BELTS NOT SLIPPING.IF ALL IS GOOD.REMOVE ALTERNATOR.LET AUTO ZONE CHECK IT.TO MAKE SURE.TURN OFF RADIO BEFORE MOVING BATTERY CABLES.SO YOU WONT LOSE RADIO CODE.YOUR CAR IS NOT GOING TO RUN RIGHT IF THE ECM DONT RECEIVE 12 VOLTS OR 13 VOLTS.

Check air filter, maybe clogged. Check leaks of vacuum on the intake manifold, maybe a broken hose.

I have a 90 chevy k1500 350 tbi with same problem! I have traced problem to... after turning on key fuel pump kicks on when u crank it over injectors shoot gas and truck starts! After few seconds injectors stop spraying and truck dies! This can happen many times over and over! Eventually sometimes truck stays running and all is great! I changed ignition module, oil pressure sending unit (which i was told controls gas after vehicle is running) fuel filter, computer, fuel pump relay, I am at a loss now! Hope this helps and hope someone can help me!

sounds like a computer issue on the burb, but i would check the IAC(idle air control) valve and the TPS(throttle position sensor) first.
I would start with the IAC on the 93'.

Not sure of your question, but it sounds like a bad fuel pump or clogged fuel filter. If it stops running after gas in tbi is consumed, it is likely the fuel pump.

Put some lucas fuel system cleaner in the fuel tank check the plugs and wires and check the air filter and see if there is a bad smell like rotten eggs when you first start it. does it use a lot of gas