1996 yukon gt frustrating issue

[keeptheedge144]

ok so I have a 1996 Yukon gt 5.7 4x4. I am having a issue we have been chasing for a while now and cant figure it out.
At 50 mph and higher when just cruise I get a random bang it feels like a misfire but I have no codes for one.
I have replaced plugs, wires, distributor, coil, fuel pump, rebuilt transfer case, rebuilt rear, new fuel lines, and 02 sensors everything we could possibly think of. Any ideas would be greatly appreciated. Im leaning towards trans issue but I also don't have any codes for that.

 

[SunlitComet]

does your gear indicator go out at the moment the bang happens? Are you saying this happens when using cruise control or just moving along smoothly?

 

[keeptheedge144]

it just happens when im moving along smoothly, and its random. I have taken it out of over drive on the higher and stayed in 3rd gear and it happens less. Its frustrating especially since I have no codes to chase the issue.

 

[SunlitComet]

Does your cruise control work and if so does it stay active when this happens? Can you retrieve the cylinder misfire history. It will show any random misfires well before a code is locked in.

 

[keeptheedge144]

yes my cruise does work fine and it stays working when the issue happens. I have the history and i have no misfires present.

 

[SunlitComet]

Next thing that comes to mind is a gear tooth jumping perhaps or a really broken suspension component.

 

[keeptheedge144]

gears are good had them checked out when rear was done, and the suspension is new all the way around including the whole front end.

 

[SunlitComet]

broken drivetrain mounts or even a binding component from incorrect installation.

 

[keeptheedge144]

i was having the issue before everything was replaced. could it possibly be transmission or maybe torque converter? They are really the only things i havent replaced.

 

[SunlitComet]

that is why i asked about cc and gear indicator. i was trying to eliminate a brake switch or power loss issue causing issues with those two parts. To really see the details of what happens in those components you need as scanner that can read proprietary gm data and preferably bi-directional coms as well. that will let you get into the heart of the system and see the input data on the pcm to understand what this or that circuit of any kind is doing. if you are convinced those parts are suspect you need better diagnostics. a basic code reader can read codes, live or in history but not much more then that.