2015 GM 3500 6.0L - Need help with engine stumble

I pulled the tank on a 2017 2500 Duramax not to long ago & was pretty easy, The exhaust is on the passenger side on both diesel & gas trucks.

Remove the 3 screws on the filler neck mount, Remove plastic shield if equipped, Disconnect the lines, Remove the straps....Shift the tank away from the frame rail & disconnect the filler hose, Lower the tank 'til you can unplug the electrical connector.
it is the front tank correct?
 
Front is the primary tank
Of course, that one is 100 bucks more. It comes with the tank pressure sensor.

Got sidetracked, my daughters Tahoe all upon a sudden developed a pretty bad leak, worked on that today.

Thanks for the help BTW. I will post back after I get the new pump in. Man I need a lift.
 
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With those negative fuel trims, your engine is running rich. Since you replaced the O2 sensors and injectors with original GM parts, the next thing I would check is the MAF sensor. What are your gps with it running at idle? Is your coolant temp sensor reading normal?
 
What are your gps with it running at idle?
right there hovering around 599-6, near perfect, and frequency matches tune aswell
Is your coolant temp sensor reading normal?
yes

my fuel pump is 5 psi high though. That is the next thing I am going to change the pump

will report back likely tommorrw evening when that is done, thnaks
 
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Not sure if this has it. I had seen quite a few of the 2007-2013 need the alcoholic composition sensor reset. They will cause driveability issues and no lights. Kind of an odd one to track down but had a few of them in my gm days
 
Replace the fuel pump
Well did that with success today. Guess what. Same thing. Factory fuel pump, from the dealer, by VIN.

Key on up to 65, then drops to 58 now, then at start back to 65.

I did find something a bit interesting though. I am eating dinner now, but wanted to reply to this ASAP. Headed back to the dungeon now to see if what I found had an effect. If not, explosives usually work.
 
Replace the fuel pump
Well did that with success today. Guess what. Same thing. Factory fuel pump, from the dealer, by VIN.

Key on up to 65, then drops to 58 now, then at start back to 65.

I did find something a bit interesting though. I am eating dinner now, but wanted to reply to this ASAP. Headed back to the dungeon now to see if what I found had an effect. If not, explosives usually work.
 
I did not, Strange as I monitor fuel pressure on many LSx engines & the pressure always matches the calibration as it's a key component in expected injector flow rate.

Starting to question the accuracy of the gauge?
 
I did not, Strange as I monitor fuel pressure on many LSx engines & the pressure always matches the calibration as it's a key component in expected injector flow rate.

Starting to question the accuracy of the gauge?
i guess. it is a mechanical gauge. i started to intermittently see random misfires on various cylinders, and fuel tank pressure show -91 psi on Hpt scanner ......which is impossible. i am starting to think it might be the computer. not aure how much else there can be. tank sensor was included with new phmp as an assembly fyi

i am going to see if i can save a datalog on hpt and send it too you once i get a chance.

I did find a fault with the evap vent valve. it was commaned open, and flow was checked with smoke, but i took the thing off and commanded it open.......it was not opening al the way, maybe 10%. i took the valve apart and cleaned it, now opening fully, but had no effect of fuel trim.

so new fuel pump, injectors, evap canister and purge.

i even swapped coils, and the "misfire" did not move.....although they are intermittent. engine idles smooth and runs smooth sometimes with very reduced power.
 
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