92 305 TBI
I'm pretty sure my fuel pump is going bad again but I just want to run it by everyone. My car started "wavy" idling and sometimes stalling and I'd get huff puff acceleration. I changed my original fuel pump last year and used the A/C kit from Mexico. (http://amzn.to/2pD1bvt)

Anyway I changed the original IAC just because it was old and rusty, TPS since it was a lifetime replacement already and tested no leaks for the vacuum. I just popped on the Actron TBI fuel pressure T-fitting with gauge and it reads a very steady 7psi. I'm going to change my fuel filter real quick which I also changed last year but I'm not too confident it's that. Does everyone agree the evidence is there for the failing pump? That kit is no longer available on Amazon but is the AC pump the best bet? I'm not sure if the pump in that kit is the actual US OEM model or not like this one appears to be ---> http://amzn.to/2DWccLm

 

Could be poor wiring, could be failed pump, could be failed pressure regulator.

Before you spend money, you need to verify voltage to the pump, WITH THE PUMP RUNNING, AS CLOSE TO THE PUMP AS YOU CAN GET. Keep in mind that the in-tank wire harness is known to have corrosion problems, too. You need to check for voltage on the ground wire WITH THE PUMP RUNNING. You should have battery voltage -two volts on the supply side, and not more than 1 volt on the ground side. This is three volts of voltage drop, which is "too much" but about all you can expect from the under-sized wiring used by GM.

After you have checked (and repaired as needed) the wire harness to the pump so that it has adequate power and ground, that, you need to plug the fuel return hose to see the maximum pressure the pump can put out. Should be ~15 psi or so. If not, the pump has failed or the filter sock is plugged.

 

It was the fuel pump. Since the AC Delco went out in a year I went with Bosch. Let's hope it lasts a little longer.