Chevrolet Repair: 1996 K1500 hard starting, fuel pressure gauge, fuel pressure regulator

Question
Fuel pressure is bouncing all around the place and not holding pressure.
Injector cleaner did not improve the situation. Since I have purchased it the idle is getting worse. Could it be a pressure regulator and or dirty injectors?

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Followup To
Question -
I have recently purchased a 1996 Suburban K1500 5.7L Vortec. I have difficulty starting it. I have to depress the pedal a little for it to start. I have replaced the plugs, wires, cap, rotor and fuel filter. I have also ran a fuel injector cleaner through it. It has an extended starting time. I borrowed a Mac tools analysier and I seem to have misfires on spark plugs 1 (most misfires) then 3 and 5. The TPS ranges o to 100% alright. There are no re-occuring codes coming up although I did see Ho2 records stored, but no check engine light indicator came up.
I do not know how to interpret the scantool.
Any help would be appreciated.

Derek
Answer -
Hi Derek, First if you need to step on the gas pedal just a little for it to start then it sounds like the IAC motor isn't working. I haven't seen too many of these go bad though. Hard starting on these truck leads me to the fuel pump. I would install a fuel pressure gauge on the fuel rail and watch it when you go to start the engine. It needs to be 55lbs or higher and should be there the minute you turn the key on. For the misfire I would run a can of injector cleaner that goes on the fuel rail tap, not the stuff you pour into the tank. This will clean the injectors and works well.

Let me know how you make out


Have a Nice Day       Mark

Answer
If you have good fuel pressure then I would say the fuel pressure regulator is bad. This is located under the upper intake manifold, the plastic part. They can leak gas and cause it to run rough. The pump will not make the gauge bounce, the regulator will.

Mark