2007 Power Wagon G56 - Hemi

[b0bc]

I picked up a 2007 Power Wagon with G56 in Feb of 2025. The truck runs fantastic, no issues no codes and I've put nearly 15k miles on it. The one issue that I can't seem to figure out is this throttle lag at times. I am trying to determine if there is anything I can do to correct it or if it is just normal behavior.

When coming to a stop and the RPMs are dropping, there is zero throttle response. For example, just push in the clutch and try to blip the throttle and absolutely NOTHING happens. Once the RPMs drop down to idle all is good, response is back.

I even ordered a diablosport tuner and have so far applied the 87 tune (until I run the 89 out of my current tank) and upped the throttle boost to 20%, this is clearly felt but the same issue persists, dead throttle when RPMs are dropping. I cleaned the throttle body, wasn't overly dirty but a bit sticky but no change. Am I missing something or is that just how these thing behave?

 

[Recoil]

Any stored or pending codes?

 

[mtnrider]

Try putting it in neutral as you are slowing down and let the clutch out then see what the throttle does?

.

 

[b0bc]

So I think I may have answer here. I've posted this on a few forums and reddit so I'll combine the basics here in case it helps anyone. On the reddit post someone suggested monitoring APP1/2 and throttle position to see if during this lag I was getting any response and opening of the throttle. I confirmed that all was good except when dropping down from 2k to 1k. Another post mentioned some additional information that confirms those tests as the natural behavior.

from jbjacks (maybe a member on here too, not sure):
What you are experiencing is a hardcoded feature—or rather, a rather annoying programming strategy—courtesy of Chrysler's Powertrain Control Module (PCM). Deceleration Fuel Cut-Off (DFCO) & Anti-Stall Logic When you lift off the accelerator in a drive-by-wire Hemi, the PCM enters Deceleration Fuel Cut-Off (DFCO) to save fuel and manage emissions. During this overrun state—specifically as engine speed cascades down from roughly 2,000 RPM toward 1,000 RPM—the PCM intentionally locks out and ignores driver Accelerator Pedal Position (APP) inputs. Because your Power Wagon sports the manual G56 transmission rather than an automatic, you feel this lockout in stark clarity:

• What the computer expects: You off the throttle, coasting in gear, engine braking down to an idle.
• What you are doing: Pushing the clutch in midway through that RPM drop and blipping the throttle to heel-toe or match revs.

The PCM's logic is locked in its "decel overrun" state until the crank signal registers that the engine has successfully settled down to target idle speed. Until it hits that floor, the ECM treats any driver throttle request as a transient error or unwanted rev rise and refuses to open the throttle blade. That is why bumping up the throttle boost on your Diablo tuner doesn't touch it—the tuner scales the pedal curve, but it doesn't override the factory DFCO lock-out routine. Primary Troubleshooting Steps If you'd like to confirm the logic or try to mitigate the lag, a few avenues exist:

1. Verify APP & ETC Live Data: If you have access to a tool like AlfaOBD(which is practically indispensable for late-model Mopar trucks), monitor the APP Sensor 1/2 volts against Commanded Throttle Position during a decel coat. You will likely witness the pedal voltage spike when you blip it, while the commanded throttle blade position remains flat at 0% until idle is achieved.
   1. Which I did and confirmed no APP1/2 or throttle change in the RPM range.
2. Perform an Electronic Throttle Control (ETC) Relearn:
   • Turn the key to RUN (engine off).
   • Wait for the dash lights to clear.
   • Slowly depress the accelerator pedal all the way to the floor over 5 seconds.
   • Slowly release it back to rest over 5 seconds.
   • Turn key OFF, wait 10 seconds, then start.
   • This ensures the sweep voltages are fully calibrated, though it won't entirely erase the factory overrun logic.
3. Custom PCM Calibration: Generic canned tunes (like the pre-loaded Diablo 87/91 tunes) retain factory DFCO parameters. A custom CMR tuner (such as Hemifeeever or Jay Greene) can modify the decel entry/exit thresholds and disable or shorten the throttle-inhibit delays in the tune file itself.

 

[Recoil]

Curious if you tried #2 and if so, what was the outcome?