Intermittent miss

[Dvdtactical]

Looked and didn't see same issue...

2001 GMC Yukon SLT 5.3 4x4 Pewter...

Computer showed misfire on right bank, fix by doing the usual plugs, wires coil packs. Turned out it was a bad injector. Replaced right 4. Left 4 rail feels really stuck and didn't want to break it, but problem went away for months. Now I get flashing miss engine light and sulfur smell from tail pipe. So I R&R all O2 sensors. Now truck starts and purrs for 20 minutes give or take a few, and has an intermittent miss that feels different than the original and it comes and goes. Would love to change left bank injectors but don't want to break anything. Any tips beyond being careful or buy a spare?

 

[OR VietVet]

First tip. Post any and all CEL codes.

 

[Tahoe14]

Hopefully, this will be moved to the 2001 section, not the 2021 section. @Miami-Dade

 

[Fless]

Hopefully, this will be moved to the 2001 section, not the 2021 section. @Miami-Dade

Done.

 

[Fless]

Remove the rails with some gentle persuasion and count on using new o-rings so they seal when you reinstall.

 

[nonickatall]

And check if your connectors on the injectors sits correct. I had that once that one has unlocked and I had misfire detected on cylinder 2, but cylinder 7 connector was loose...

 

[Dvdtactical]

My bad posting in the 2021 section. Only engine related code was P0302, I think. That's the misfire on #2 cylinder code. Other code was bad ground in abs computer. Found #2 coil was not producing spark. Moved it to #4 and code presented there. Changed coil and seems good for now. Waiting on the next gremlin.