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. is this normal, or should it be holding the pressure?

the car is an 88 GTA that only has a catback and a hypertech stage 2 chip. also, the AIR pump has been disconnected, and diverter valve removed. 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.

 

altho the fuel press sounds a bit low (it should always be at 42 psi) i would be willing to bet on either your maf sensor or your tps sensor, https://www.thirdgen.org/tpimod2 that link about the TPS sensor is good if you dont have the scanner. also, if you buy another TPS sensor they will have detailed instructions on how to calibrate it using some 18ga. wires and a voltmeter.

 

gramps,
i have verified my TPS sensor working properly from a previous repair actually regarding a MAF code 34. the code is no longer on after i replaced a non firing injector.

 

Check for vacuum leaks! You want to pay particular attention to vacuum lines coming off the throttle body. I found my biggest problem was the Charcoal cannister and the right breather line feed into the throttle body.

I had the same poor cold start function as well as a code 44 (lean mixture) problem. After repairing these things, the cold start works great and the idle is now stable.

 

can you go into alil more detail. im having lean code 44 problems and rough cold start issues too. car was running better having oil flush and new fuel filter. but now after doign some modifications seems worse with still jsut a code 44 to show for it.