2012 Suburban Misfire #5 drama

[hagar]

On the off chance that the crankshaft position sensor or the cam position sensor have been replaced or could otherwise be suspect (or not), do a CASE relearn just to rule it out.

That is a great suggestion. I looked at a buddies 6 liter with high miles a few years back that was misfiring, though his was on a few cylinders, and couldn't find anything wrong with it. Did a crank re learn and it smoothed it right out and ran great until it got stolen a few months ago. In his case I think the timing chain was getting so much slack from the mileage, it was throwing off the cam to crank timing. Couldn't hurt to try.

 

[2015TahoePPV]

my 2010 had a strangely similar issue once, I'd circle back to that bundle of wires near the power steering pump. I've seen a few threads out there on the internet about those wires rubbing through and shorting, and the weird nature of this one feels very similar. Your P219A could also be indicative of an issue with that side's injector's harness. I'd get the pin outs to the ECM and ohm the connector from the injector harness to the ECM and with your meter connected I'm betting you will see the issue if you jiggle that harness by the power steering pump.

 

[bazec]

i had a situation with #4 misfire after much head scratching found no crank compression good. Running compression low #4 V-lom
leak by killing #4 lifters. Changed V-Lom no more problems

 

[bazec]

i had a situation with #4 misfire after much head scratching found no crank compression good. Running compression low #4 V-lom
leak by killing #4 lifters. Changed V-Lom no more problems

2014 Tahoe 5.3

 

[Rush1]

Try a crank position sensor relearn , That usually takes care of a phantom cylinder miss

 

[West 1]

Compression was good so I would certainly start with a scan tool that can shut down the injectors one at a time and see if the power balance is normal. The injector in 5 might be getting bad signals from the computer. I believe they only open when supplied a ground circuit so maybe the injector wire is shorted to ground somewhere hanging the injector open? Your fuel trims are trying to pull fuel out of bank 1 so extra fuel is getting there from somewhere. It is either no spark not burning the fuel or extra fuel dumping in from the injector in #5.

 

[solli5pack]

Definitely going to need a scanner that shows live data otherwise all your doing is taking guesses. Even though you're getting a P0305 you can't even be sure the cyl 5 is the issue without verification using a scanner.