Does your fuel pressure hold steady after you pressurize the system, then turn the key off? I am starting to wonder if there is a slight drip from something that is causing a rich condition...

There is definitely something that is causing it to choke down...

 

to me its bad news but im sure it might give you something else to work with.

I went and bought another iac becasue the first one i bought looked like someone bought and tried and took back
so with the new one in i took it for a drive becasue on the first one i failed to read my haynes book fully to see my car had to get to temp first (duh) so with that acting the same way with the new one in i decided to check all electrical connects from the IAC to the relay and it was terrible all this black greasy stuff gooked on in three ports on both relays so i cleaned out the plastic connectors with some contact cleaner and plugged both of them back in and started it up.

to my surprise it stareted up and ran perfect for about ten minutes! then it shot a service engine soon light at me so i turned it off and jumped the ground and diagnostic on my connector and it said it was the IAC so i decided to clear the code and run it again to see if it would shoot the code at me again? did that started it up and it was back to its normal self almost choking out like you said then i put the new IAC on and tried it same thing i even pulled the relays out and shot cleaned those out good. i used the contact spray again (not sure if that could ruin them) but took it for a drive and im still in the same boat but it confuses me alot on why it ran so good for so long till i cleared it?

also i went to start it back up and i accidently had the jumper still in and i pulled it out and turned the key off then started it before it went back to normal lopeing and stalling... and sometimes when i let it stall out real bad like it slows down alot and stumbles a couple times and stalls out, i start it up it revs really high then drops down to regular idel speed


ohh and the vacum kit i bought also tests feul pressure but i dont think i have the right connector to plug in on the bleeder vavle on the nut kit coming out the back of the plenum should a type of thing like that be carried at a local auto parts store? it also came with a t connector and a couple of other fitting but i dont see how it could be used to test pressure outside of thatspecific fitting to go on the bleeder vavle?

 

If it is a combination vac/pressure gauge, then it probably doesn't go high enough for the fuel pressure that your engine requires (50+psi).

Have you determined where all of that "grease" came from? Sounds like something cooked itself at the relays.

 

No i havnt yet we checked what seemed to be the o2 sensor connections and iac im planning to follow all of them tomorrow.

is there a simple way to test them without actually pulling apart harnesses?

also i went and messed witht he relays again and got it to idle normal so once this happened i went for a drive pulled out of the drive way and hit the gas and it stumbled real bad hesitated more than the usual did this for a good bit and now its stalling out as soon as i stop like a two three second delay from full stop to stall also there is a weird noise im getting from the rear and off the relay
sounds like the feul pump running after the engine stalls for about four sec then a click noise from the pump and the relay?

I have 4 videos here for you i want to get one of the noise so i figured getting the idle would be good to


Driving Stall Fuel pump noise Starting stall Idle and stall

 

Fuel pump sounds normal.

It definitely seems like an electrical problem and seeing as how messing with the relays caused things to work, I think that is where you need to focus your attention.

 

Just got back from first day of school with the kids.

im aboutto check all the electrical as soon as it cools down.

let ya know what i find!


i hope i find it

 

would a bad alt cause my stalling problem becasue my bat does drops down as soon as the engine stalls out

and drains pretty quickly there after?

 

I just joined because I'm having the same issue with my '93 Bravada vin W....and I have just found this TSB:

No Start, Hard Start, Rough Idle After Start (Clean CPI Poppet Valve) #99-06-01-022 - (12/21/1999)
No Start, Hard Start, Or Rough Idle After Start (Clean CPI Poppet Valves)
1992-1995 Chevrolet and GMC M/L, S/T Models
1992-1995 Oldsmobile Bravada
with 4.3 L Engine (VIN W RPO L35)
Condition
Some customers may comment on no start, hard start, rough idle after start, surge, or other driveability concerns related to the fuel system (clean CPI Poppet nozzles).
Cause
Under certain conditions, fuel elements may deposit on the poppet *****, seats, or pintles, which can cause the poppet ***** to stick in either an open or closed position.
Correction
Follow the Strategy-Based diagnostics for your customer's specific driveability concern. If diagnosis leads to sticking poppet nozzles, this cleaning procedure should be performed prior to replacement of the CPI injector.
CPI Injector Cleaning Procedure
Loosen the fuel filler cap to relieve vapor pressure in the fuel tank.
Raise the vehicle on a hoist.

Locate the underbody fuel line (1) junction point:
For S/T and L-van, it is along the left frame rail at approximately mid-vehicle.
For M-van, it is behind the left-front wheel housing.
Caution
Considerable fuel leakage may occur. Make sure that protective eyewear is worn, and that suitable fuel containment measures are taken.

Loosen and disconnect both the pressure and return lines at their junction points. The fittings towards the front of the vehicle (both pressure and return) have "male" fittings, and the fittings towards the rear of the vehicle have "female" fittings.


Install the J 44466-2 (1) (this hose has two 90 degree male fittings and no service port) to the "fuel tank" side of the fuel pressure and return lines. Installation of this hose eliminates the need to electrically disable the fuel pump and allows fuel to recirculate to the fuel tank.


Important
This cleaning procedure and service tools separate the fuel tank and pump from the cleaning process. Do not allow the Top Engine Cleaner solution to reach the fuel tank and/or pump. Top Engine Cleaner solution may cause a failure of the fuel pump.

Install the J 44466-1 (3) (this hose has two female fittings and a service port) to the "engine side" of the fuel pressure and return lines. Installation of this hose creates a "loop" through the hose and the engine side of the fuel system.


Obtain the J 35800-A (2). Make sure the valve at the bottom of the canister (3) is closed.
Remove the canister top and add 24 ml (0.8 fl.oz.) Top Engine Cleaner, GM P/N 1050002 (Canada P/N 992872), to the canister.
Fill the remainder of the canister with regular unleaded gasoline and install the canister top.
Suspend J 35800-A from a convenient location under the vehicle.
Connect the hose from J 35800-A to the service port on the J 44466-1.
Open the valve (3) at the bottom of J 35800-A.
Connect a "shop air" source to the fitting at the top of J 35800-A and adjust the regulator (1) to 75 psi.
Lower the vehicle to a convenient height and start the vehicle. It may be necessary to re-adjust the J 35800-A pressure regulator to maintain 75 psi.
Let the vehicle run at idle until the canister is empty and the vehicle stalls.
Turn OFF the vehicle ignition switch.
Raise the vehicle.
Remove the shop air supply from J 35800-A.
Depressurize J 35800-A.
Disconnect J 35800-A from J 44466-1.
Remove J 44466-1 and J 44466-2 from the vehicle fuel lines.
Re-connect the vehicle fuel lines.
Lower the vehicle.
Add one (1) ounce of Port Fuel Injector Cleaner, GM P/N 12345104 (Canada GM P/N 10953467), to the vehicle's fuel tank for each gallon of gasoline estimated to be in the tank. Instruct the customer to add the remainder of the bottle of Port Fuel Injector Cleaner to the vehicle's fuel tank at the next fill-up.
Tighten the fuel tank filler cap.
Start the engine and check for fuel leaks.
Clear any Powertrain DTC codes as required.
Advise the customer to change brands of fuel.
Parts Information
Part Number
Description
1050002
Top Engine Cleaner (U.S.)
992872
Top Engine Cleaner (Canada)
12345104
Port Fuel Injector Cleaner
10953467
Port Fuel Injector Cleaner (Canada)
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
J5645
Injector, Fuel - Clean
0.8

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
Images available only to Customers.

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© Copyright General Motors Corporation. All Rights Reserved.

 

I actually did my whole replacement of fpr and nut kit without cleaning those i will make sure to check the condition of them when i have the plenum off the check the cap and plugs!

thanks for the tip



i dont think its that though it ran good when i started messing twith the electrical so im bettin on it being electrical!

 

Mine improves when I do anything with the EGR - until it warms up.

I did replace the FPR because mine had started leaking, but I didn't check the poppets either.

There's another TSB about using GMs top engine cleaner to clean out the carbon in the upper engine passages - something about letting it suck into a vacuum hose, etc. Supposedly there are instructions on the can. I'm going to check that out, too, since my EGR seems to cause issues and get better briefly after I mess with it. Perhaps chunks of carbon are getting loose and clogging it again, right after I've cleaned it.