ImperialStaudt

I have a 2001 Suburban LT 4x4 5.3L and it died at a light one day. Felt fuel related and wouldn't restart.

So I got a new fuel pump and filter and still wouldn't run after starting. I replaced the original fuel regulator while I was there. Seemed to help some. I really need to get a fuel pressure check done.

But with a newly fuel system it still have the same problem, swapped the relay with another one to make sure that wasn't the problem.

Thinking it might be sensor-ish I tried cleaning the TB and IACV. I cleaned the MAF, I tried unplugging it and running and didn't do much different, ran better with out the intake tube connected but then back to the same problem (might be due to carb cleaner down the intake/TB.

Pulled the code and it was MAF reading too low - which I assume to being unplugged.

Thinking it might be TPS but I really want to find the impedance values to test mine.

Cleaned the IACV and the spot it settles into in the TB. To see if that was an issue.

It starts up after a couple attempts and then it idles fine for a couple seconds then sputters onto its face.

So I searched some but I am not sure where to start.

Side note but new battery since i have been starting so much. I purged some the fuel rail to make sure the air was out, not sure it there is a real method to it.

Where to next?

in2pro

Welcome to the forum...
Do check the fuel pressure
Do check that you have the correct and clean air cleaner filter since you said it ran a bit better without the air tube, that tells me you might have a air supply issue but you could be on track with the IAC.
What do the plugs look like ?
Perform a compression check?
The starts and runs for a bit, then stalls leads me to think its getting bad info from the O2 sensors when they go into closed loop after warming up...
How many miles do you have, possible clogged cats stalling out the engine?

ImperialStaudt

311k but hasn't missed a beat in the last 20k that I have owned it for. Before it was a friend's and his family from the beginning.

I got a HF fuel pressure gauge and it looks like I am getting 12 psi which seems crazy after a new pump, filter and regulator. So since it had low fuel~1/8 tank, I am going to fuel it up some more and see if that helps the pump prime.

in2pro

12 psi is too low... should be in the 50-65 psi range and solid...
Use the gauge on another vehicle to check... if you are really getting 12 psi your new pump is no good, is it OEM i.e. AC Delco or Delphi or aftermarket?

ImperialStaudt

Aftermarket Rock auto special, I didn't read about the low end pumps being bad from the factory before I ordered.

Yeah I am going to test the gauge to make sure but the system was losing prime/pressure when left too.