original symptoms: vehicle stalls the first time you start it when cold. for the first minute-ish, it bogs when you press the gas pedal, and then goes. after a minute or two, its fine.
my original thought was the fuel pressure regulator. causing the engine to flood slightly overnight

brought my car to a speed shop and they put it on the dyno and read the A/F. it was about 15:1 across the RPM range. they said that 15:1 is so bad, they they didnt even want to do another pull on the dyno.

i just got a fuel pressure tester, and the vehicle reads about 43psi at idle with the vacuum line on the regulator disconnected, and about 38-39 with it connected. i rev up the motor a little by hand, and the pressure doesnt go up at all. i thought it should go up when you rev the motor?

i turned off the car and let it sit for 30 minutes and the pressure is down to about 13psi, and 0 in about an hour. is this normal, or should it be holding the pressure?

the car is an 88 GTA that only has a catback and a hypertech thermomaster. also, the AIR system has been deleted physically. i have recently changed the: 02, cat, plugs, wires, cap, rotor, coil, maf power and burn off relays, pcv, almost all vacuum lines, one non-firing injector, fuel filter, and the previous owner replaced the fuel pump.

 

I am not sure but I do believe that you should not be losing fuel pressure over time. Because essentially it should be a sealed system so when it is pressurized it should stay pressurized unless you have a leak somewhere.

 

The first problem sounds like the cold start injector system possibly,but the running lean is a separate problem.My fuel pressure generally stays at about 41 psi all the time.The computer should vary the injector pulse width to compensate for that lower pressure.What is your integrator and block learn doing?

 

From my 1988 IROC manual.
Possible causes.

1. Fuel pump check valve
2. Regulator diaphram
3. Leaky injectors

Checking for leakage.

1. Install a fuel pressure gage on the fuel rail schraeder valve.
2. Pressurize the system by cycling the key on for a few seconds.
3. Turn the key off, and time the pressure reduction on the gage. (Initial pressure should be approximately 40 pounds per square inch (PSI), note the time it takes for a pressure drop of twenty PSI to occur. If the time exceeds twenty minutes, check valve, regulator, and fuel injectors are free of excessive leakage.
4. If the system pressure is reduced by 20 PSI or more in 20 minutes or less, then one or more of the three components mentioned are suspect.
5. Turn the key on for a few seconds to repressurize the system and clamp the rubber portion of the supply line closed using a pair of vise grips and a shop towel (to protect the fuel line from damage by the vise grips.)
6. Turn the key off, and again note the time it takes for a reduction of twenty PSI. If the time is a lot longer than the time noted in step 3, then replacement of the fuel pump is indicated.
7. If the times are similar, then repeat steps 5 and 6, only this time clamp the return line instead of the supply line. Once again note the time it takes for a twenty PSI pressure drop. If the time is a lot longer than previously, a faulty pressure regulator is indicated. If the time remains shorter than twenty minutes, leaking injectors are suspected.

To confirm that there are leaking injectors, raise the fuel rail slightly out of the inlet manifold without disconnecting any fuel lines and place a small napkin or piece of paper under each injector. Pressurize the system by cycling the key on for a few seconds then turn the key off and allow to sit for about 10 minutes.
It is not uncommon for pressure to take hours to bleed off.