Too many possible issues

[TmDreko]

I have a 2009 gmc Yukon Denali 6.2.
I was at a gas station filling up, cranked up puff of white smoke and truck started shaking. The parts store was down the road so I got codes read, misfires #7 and #4.
Replaced all plugs,all wires and only replaced two coil packs on misfire cylinders. Still nothing. Changed fuel injectors…still nothing. Cranks but won’t stay running really ruff shaking sitting or in drive or reverse. Engine lights flashing only take gas for like 4 seconds after cranking then it takes no gas even with pedal to floor. After about 5-10 seconds engine dies lights still on. I’ve also replaced fuel pump. Cam/crank sensor? Intake? Valve spring? Whole new engine?

 

[Doubeleive]

I have a 2009 gmc Yukon Denali 6.2.
I was at a gas station filling up, cranked up puff of white smoke and truck started shaking. The parts store was down the road so I got codes read, misfires #7 and #4.
Replaced all plugs,all wires and only replaced two coil packs on misfire cylinders. Still nothing. Changed fuel injectors…still nothing. Cranks but won’t stay running really ruff shaking sitting or in drive or reverse. Engine lights flashing only take gas for like 4 seconds after cranking then it takes no gas even with pedal to floor. After about 5-10 seconds engine dies lights still on. I’ve also replaced fuel pump. Cam/crank sensor? Intake? Valve spring? Whole new engine?

well some better explanation of what work has been done and the reasons for doing it would be helpful
but generally speaking a flashing check engine light means "severe misfire" if that is still the current condition, then that is what you should be concentrating on.
a good place to start is the battery cables and grounds to be sure the electrical system is intact. If there is poor power or ground it wont run right no matter what you do.
unless there was low fuel pressure (verified) with a gauge then there was probably no reason to replace the fuel pump.

 

[Marky Dissod]

Before firing the 'more expensive parts cannon' at your Denali, fire the 'less expensive parts derringer'.
@Doubeleive is right, check/clean & refasten the electrical grounds/earth paths for coils/injectors before moving on to check plugs/wires/coils/injectors.

 

[Fless]

I would think that your 6.2L engine has AFM, unless it's been tuned out or somehow defeated. If it has AFM and it's still active, it's time to pull the valve covers and see if the rocker arms are moving for the misfiring cylinders.

 

[dkad260]

Check your MAF, make sure the wires/connection is good, no rodents nest in filter box.

What services have you done to it prior to this incident? Recent work?

Any overheating issues?

Check oil dipstick for any light brown residue, trying to rule out head gasket with that.

You didn't by chance fill it with E85, or diesel? Diesel can be hard to do but have seen it done.

It acts like a MAF not working but it would throw a code for that. Also need to verify fuel pressure. The battery cables I agree is where I would start.

 

[Fless]

You didn't by chance fill it with E85, or diesel? Diesel can be hard to do but have seen it done.

This is a good thing to check -- what fuel was added to the tank?

Holes 1, 4, 6 & 7 are AFM cylinders, and can be prone to valve lifter issues.

 

[fredcook]

Did you run your own scan tool on it, and not just rely on what the auto parts store told you? Make sure you use a scan tool that can read all DTCs like GMs B, C, and U codes. Not just P codes. Need to grab some live data as well.