2008 Tahoe Fuel Delivery Issue?

[swathdiver]

Checked the gaps on your spark plugs lately? How about the wires?

 

[about20ninj45]

Two things. You need to view fuel pressure under load, or near the condition that causes the stumble. If at all possible, fuel trims and injector duty cycle. This will tell us if your fuel system is being taxed or intermittent. Your fuel should be up to the task since it's flex fuel.

If you can't figure this out, and your near metro Detroit, I can log your data and take a look at your tune for you.

 

[NarcolepticNugget]

Two things. You need to view fuel pressure under load, or near the condition that causes the stumble. If at all possible, fuel trims and injector duty cycle. This will tell us if your fuel system is being taxed or intermittent. Your fuel should be up to the task since it's flex fuel.

If you can't figure this out, and your near metro Detroit, I can log your data and take a look at your tune for you.

I'm not equipped to do this sort of stuff. I am only a little over an hour from Detroit though.

 

[NarcolepticNugget]

Checked the gaps on your spark plugs lately? How about the wires?

New spark plugs and wires about 6 months ago. They all still look fine today.

 

[about20ninj45]

I'm not equipped to do this sort of stuff. I am only a little over an hour from Detroit though.

You can get a fuel pressure test rental kit from O'Reilly or AutoZone and use that to view your fuel pressure under load, just make sure you mount it where it visible.

I would also contact the shop that tuned it and ask them for the tune file as long as it isn't locked.

I should be free this weekend so if you want to swing by, shoot me a pm

 

[Ming15237]

I am an ASE Certified Master Tech. Before you do ANY further the next thing I would check is the catalytic converters on the truck. This sounds like a classic example of a bad converter which is either melted or broken turning sideways under load and restricting exhaust flow. The test can be as simple as removing a FRONT oxygen sensor and sending a inspection camera down the hole and looking at the catalyst substrate for signs of damage. In general if you have a performance issue that clears up when you back out of the gas at higher rpm’s I always look for an exhaust flow issue first.