350 with TBI intermittent injector pulsing

The PCM (ECU does that) its part of what is called EFI, electronic fuel injection, it's a computer, that gets inputs, and uses those inputs to injector perfectly at ALL times.
what engine? 3cy. or 4? is it TBI injected or MPI injected
1 injector or 4? we need to know that first.
does it run on test fuel for 3 seconds.
when was last time it run perfect, last week last year. what?
first off stop guessing, you can go broke that way.
want to diagnosis it? the steps are easy. if fuel is good..

1. fuses good.?
2. CEL lamp glow keyon, if not ECU is bad. or bulb , it must glow.
3. compression over 150PSI on all cyl. (w.o.t = wide open throttle)
4. do a 60k, mile tune up yet, filters, spark,. and cam timing belt.?
5. if not, why wait?
6. 6: is spark good tall cylinders not just 1? is the timing way off if yes, the cam belt did slip, do not fiddle tiiming, fix the belt. first.
7. ok it now magically runs on test fuel for 3 seconds and sounds great. so we do fueling last.
8. fuel pressure tests are next. takes $20 gauge got one?
9. ill stop here, as fueling tests are long play.l..... ask. if you can get to step 9,

I think all 94 metors are TBI engines, one injector
up to 1997 inclusive.
then the 1998 offered 4cyl, MPI injected engine.


have you learned how to use flash codes (DTC) yet?
insert jumper , key on, see CEL lamp glow and flash 12s'
the crank for 5seconds, see if the flashes go to 41 or 42?
bingo if yes.
the TBI allows the mech to watch injection, at the TB.
with top hose off. you can watch it inject as person 2 cranks.
does it?
the ECU brain cuts fuel at the first sign of:

1. lost spark (to stop fires)
2. lost Cmp sensor, same .
3. TPS ground wire busted and ecu things foot is W.O.T (super secret unflood mode) (or TPS cracked in half inside)

or total loss of fuel pressure.

Replace the pickup coil in the distributor this is where you get your pulse for the injectors.

If you have spark, the computer is getting the signal to pulse the injectors.
If you have power but no ground pulse, you may have fried the driver in the computer again.
You could get a used computer from a junk yard to test it.
There could be a short in one of the injectors or the harness at the computer, or a break in the circuit from the computer, and that could kill the driver in the computer.

Check the coil, the control modual in the distributer, and the ecm. thats what controls the injectors.

E.C.M control injector pulsation, with key on check for voltage at injector harness, then reverse test light at battery and check for ground at the other wire at injector harness, crank engine ground should have pulsation if none bad E.C.M,good luck,hope this was very helpful.

Not alot to go on here especially since the problem is so intermittant. You could have the beginnings of ...fuel pump starting to go, ignition coil or ignition mudule problem, idle air control problem, tbi or injector problem, computer problem, ect,ect,ect. If the problem develops more to where it dosent start then you could check for spark, fuel pressure, injector pulse. If you want to try some inexpensive things then start by replacing the fuel filter and plugs. Take a spray bottle and while the engine is running spray down the cap and wires to see if the spark is shorting out. Otherwise take it in and see if a mechanic can find something. Trouble is if its not happening its hard to find. Good luck!

If hall effect switch was bad you wouldn't get any spark.What year 2.5L is this?Is this a 2 injector Throttle Body? The pink wire on top of injectors comes thru a 20Amp fuse controlled by the Ignition switch you should have battery voltage with key on The dark green and dark blue wires come from the pcm which are called injector drivers the drivers supply a pulsating ground if you crank the engine with a test light between either pink/dk green or pink/dk blue test light should flash dimmlythat would mean injectors are being driven but there isn't any fuel at the injector or the injectors are bad no pulse means either a bad computer ( which these drivers are known for going bad)or the computer isn't being commanded to fire the injectors.

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!

it's probably the transmission and u might have to change ur fuel pump also

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'.