Truck Wouldn't Accelerate Past 30 MPH?

[Fire29]

Hey guys, 2022 RAM Cummins 6.7L here.

So, this is the first time this issue happened to me.

Truck and trans were up to temp.

I accelerated (nothing crazy because of the rain), and the truck was shifting smoothly up to 28 mph.

Then the truck would not accelerate past that.

Gently let off the pedal, then slowly back on it, and nothing.

Pull off the road, and run codes and no codes yet.

Let it sit for about 30 seconds, and it drove perfectly afterwards.

I do have this weird vibrating noise (sorry, the best way to describe it) from the back of the cab at low speeds on the first drive of the day.

Doesn't come back until it's been sitting all night.

Called a few shops, got a few different possibilities, either the tank fuel pump is going, or the VGT is going.

Truck is deleted, upgraded valve body, and thats about it.

Doesn't strike me as a transmission issue because it's shifting fine, PSI is solid, and there are no drops.

Has anyone gone through this?

Thanks, everyone!

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[AK Bob]

Haven’t gone through this, but thinking you may have two separate issues.

On failure to accelerate past 28 mph, I would monitor the Fuel Rail Pressure actual vs. desired and the VGT actual vs. desired.

The cold start vibrating noise behind the cab could be the center carrier bearing.

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[Fire29]

Thank you!

I'll monitor those and check the carrier bearing.

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[Fire29]

Ok, quick update.

So I think it's the turbo.

Truck built about 8psi at red line, no exhaust brake, barely, and turbo spool, LOL.

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[AK Bob]

Ok, quick update.

So I think it's the turbo.

Truck built about 8psi at red line, no exhaust brake, barely, and turbo spool, LOL.

The VGT actual vs desired will confirm your suspicion.

Are you seeing any trouble codes?

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[Fire29]

No codes.

VGT desired % is moving around, but VGT actual is stuck at 72% for a moment.

It was around 65%; now it's stuck at 72%.

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[Fire29]

So I'm gonna assume it's the turbo?

LOL

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[AK Bob]

So I'm gonna assume it's the turbo?

LOL

Sounds like the turbo vanes are sticking.

I would expect to see trouble codes if the actuator were bad.

The next step would be to confirm the presence of stuck turbo vanes.

Drain the coolant, remove the actuator, and check the turbo gear paw arm to see if it will move from stop to stop with finger pressure.

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