2014 5.3 Motor Blown??

[ThatSierraOwner]

Hello all. I’m looking for some help/advice. My truck has been a nightmare. 

 

Original issue: Started running rough, visible rpm fluctuation, shifting and downshifting very hard. Originally thought the torque converter was going out again. Codes were P050D, and P0308 which is misfire on cylinder 8. Had dealer replace fuel injector bank on passenger side. 
 

Picked it back up. Started driving to work and noticed raw fuel smell as-well as a pulsing/pushing air noise. No codes. Ended being a broken pcv tube off the intake manifold. 
 

Picked it back up. Same raw fuel smell as before. This time the SES light and P0304 is on. Outer spark plug ceramic was cracked and plug wire shorted. New plug and coil wire were installed. 
 

Again still noticing smell at stops. Cylinder 4 misfire light comes on. Checked compression cylinder 4 had 110. All other cylinders on that bank were around 210. Rockers and valves all good, piston is burnt with scarred cylinder. 
 

Dealership has been good to work with and always provide answers to my questions. 
 

I’m looking for insight on what might have happened to my motor, and suggestions on what to do next… rebuild? Motor swap? Etc

 

Thanks

Edited July 22, 2023 by ThatSierraOwner

[Snowcamo]

Replace the plug wires and ignition coils.  I bet you just have a few cylinders with a mild miss fire that is not showing. Been there. 

[ThatSierraOwner]

2 hours ago, Snowcamo said:

Replace the plug wires and ignition coils.  I bet you just have a few cylinders with a mild miss fire that is not showing. Been there. 

Already replaced. Compression is still low.

[Snowcamo]

Ya i missed the low comp.  It's time for a rebuild unless a valve is not sealing even then ya may as well just rebuild or 6.2 it

[JC702]

The cylinder is scored so time for a rebuilt motor. 

[Snowcamo]

Yep.