2014 Tahoe PPV P0308 help!

[Kristopherbeats]

I have a 2014 Tahoe ppv 122k

Doesn’t burn a drop of oil. No head noise.
I have the code p0308 misfire cylinder 8

Changed plugs, wires
Swapped coil pack from Cylinder #2 to #8
Swapped Fuel Injector from cylinder #2 to #8
Fuel Rail Pressure 58psi cold.
1-8 110-115 psi on compression test. Cylinder #8 110psi

Anything over 1100 rpms I don’t have a problem. I drive it 50 miles a day and it seems to only do it a few times a day. If I’m in a high gear at 45 mph and try to give it a little gas it will stumble then clear up.
I’ve sprayed carb cleaner around the intake and did not notice any idle change .


I’ve checked pins on injector and coil pack look clean and connected well.


I’m lost can some one give me some guidance on the next steps ?

Thanks for any input.


Sent from my iPhone using Tapatalk

 

[gpracer1]

110 psi seems low.

 

[Kristopherbeats]

I was under the impression that as long as there not more then 10% out of wack that it wasn’t bad. Also I didn’t have my throttle wide open witch could of lowered my results


Sent from my iPhone using Tapatalk

 

[gpracer1]

Best is warmed up engine, all plugs out, disable fuel pump, crank with WOT.

 

[thompsoj22]

ill catch flack for this one but if it were mine and i wanted to rule out lifters bleeding down on that cylinder i would simply dump the 5/30 and replace with 20/50. Dont even change the filter, simply drive as usual and see if the code frequency changes or go's away. If it changes it's a lifter if no change it could be a sticky stem/guide on that cyl? Either way it is a cheap trouble shooting method. i would just use some castrol GTX and no high 5k rpm runs, just normal drive. Whatever it does, go back to your normal oil with a new filter when you decide to. It wont hurt your engine. Im assuming the ECM is not the cause of that specific cyl misfire.