2011 Tahoe sputters under low RPM

[divetime1972]

My problem is definitely worse with the AC on. Will check on the 4 cy vs 8cy.

 

[PG01]

Drop truck into M paddle shift up to 5(6sp trans right?) it will not go into v4 at all and stay in v8, see what it does......2cents

 

[DStarr02]

When i found mine arching, it just made it run rough intermittently, the worst was at idle and soft throttle, would get up and go when i got on it, figure the rpm's made up for the cylinder down, but it also wasn't throwing any codes at all. But that was older tech, would think the newer stuff would catch it.

 

[DStarr02]

Another thought, i was able to figure out the wires and plugs due to if i rotated the wires back and forth a couple times on the plug ends and distributor contacts, it would run smoother for a little while. I figured it cleaned of some corrosion or something, just don't do it while it's running (probably already know that, just encase).

 

[TheLoveClaw]

So I pot the shifter in M5 and drive around. Hit a state highway and was cruising at 60 and it started happening on the straightaways. It was weird because it was almost timed. Nothing for a second to second and a half and then bump-bada-bump-bump. Over and over again until I gave it more gas.

 

[PG01]

So its not afm or dod, did you pull/look at the plugs and check the wires?

 

[DStarr02]

I agree, prolly got a bad wire, plug or coil starting to go.

 

[TheLoveClaw]

So I checked for arching but couldn't find any. I have replaced all the plugs and wires, and it was doing the same thing before and after so I don't think it's the plugs or wires. I did think it could be a coil. I can't really tell if it does it when the engine is cold which points to a coil as well. Does anyone know how to test and figure out if the coil is going bad or do we just wait until it finally goes?

When I changed the plugs and wires I notice 2 of the plugs seemed a bit fouled. The plugs came from pistons 8 and 6.

 

[kbuskill]

Plug in a tech2 and make sure all the coils are firing. "Usually" coils are like light bulbs, there either good or bad.

 

[TheLoveClaw]

I don't have access to a Tech2, but I did try an adjustable ignition spark tester. I tested all 8 ignition coils and every one of them was able to make the jump at 35kV.

New plugs, new wires and good coils so that rules out the ignition system. I guess it's got to be something else.