Hesitating to Start

[justirv]

At the time I bought it off Amazon, but I stopped buying OEM parts from Amazon. I’m confident it’s not the fuel pump because this issue was occurring before I replaced it. The fuel pressure specs are as follows before I replaced the fuel pump.

46 psi when key was on but engine off.
42 psi with engine running
42 psi after engine was ofF

I agree with you on re: AMZ "oem" parts, I quit ordering those from them several years ago. Your fuel pressure sounds low to me, I do not recall actual spec (maybe 58psi?), with a bit of difference between gas and flex. Check the fuel pressure regulator on the rail? That bleeding off pressure could also affect your hard starts.

 

[Fless]

It would be helpful if there was some vehicle and drivetrain info in your signature. Not all are the same.

For fuel pressure, according to Haynes:
KOEO
Flex Fuel: 48-54 psi
Non-Flex: 55-62 psi

Either way the KOEO pressure is below the minimum. If it's a FF system has the inline fuel filter been changed?

 

[nonickatall]

These were the fuel pressure readings before I replace the fuel pump.

46 psi when key was on but engine off.
42 psi with engine running
42 psi after engine was off

Isn't that a little low? Should be between 55-62 PSI, so you should swap the fuel pressure regulator and fuel filter, if your Tahoe has one. Some of the cars have the fuel filter inside the fuel pump.

 

[diezelraccoon]

Isn't that a little low? Should be between 55-62 PSI, so you should swap the fuel pressure regulator and fuel filter, if your Tahoe has one. Some of the cars have the fuel filter inside the fuel pump.

Well since I relaxed the entire fuel pump assembly that takes care of fuel filter if it was on it, but I believe mine is elsewhere.
I will try replacing that and fuel pressure regulator.

 

[diezelraccoon]

It would be helpful if there was some vehicle and drivetrain info in your signature. Not all are the same.

For fuel pressure, according to Haynes:
KOEO
Flex Fuel: 48-54 psi
Non-Flex: 55-62 psi

Either way the KOEO pressure is below the minimum. If it's a FF system has the inline fuel filter been changed?

Not to my knowledge but I will replace it along with fuel pressure regulator

 

[Fless]

FYI the FPR has no effect on the fuel pressure when running KOEO tests. On your system it works using supplied manifold vacuum, which is nonexistent when the engine isn't running.