Intermittent "dead spot" in accelerator pedal.

[CSM]

Over the past few days i've found that there is a dead spot in my accelerator pedal where either right off idle or at cruise at about 1/4 pedal the motor will drop in output, and if in OD the converter will pop in and out of lockup as if I were making wild swings with the accelerator pedal. I haven't checked for codes yet, but I haven't seen a check engine light either. Otherwise the truck runs great. New batteries recently, and I really should check contacts and grounds, but its a weird issue regardless. Any bright ideas?

[diesel4life]

Sounds like it could be the tc lock - unlock issue Ive heard about on here although Ive never experienced it. Could also be an apps issue when mine went out I could keep a steady position of the throttle with my foot but the rpms were going all over the place. But I would think you would have thrown a code if that was the case. So, if no codes, possibly bad or loose connections / grounds? Im not sure if the tc lock issue would bring any codes up or not?

[CSM]

Threw a code this morning! P0122 on the ECM only. 1693 on the PCM... off to see what that means.

And... Thanks to Mike: http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/36-apps-sensor-error-codes

DTC P0122: ACCELERATOR POSITION SENSOR SIGNAL VOLTAGE TOO LOW

Description

Accelerator Pedal Position Sensor (APPS) voltage is monitored when engine is running. DTC may be stored if low voltage is detected on APPS signal circuit or low voltage is detected between Engine Control Module (ECM) and Powertrain Control Module (PCM). Possible causes are: defective APPS, defective ECM, defective PCM, or defective connectors or wiring.

Testing

[*]Turn ignition on with engine off. Using scan tool, check for ECM and PCM DTCs. If DTC P0122 is stored in both ECM and PCM, go to next step. If DTC P0122 is not stored in both ECM and PCM, go to step 8 .

[*]Turn ignition off. Disconnect APPS sensor connector. APPS is located on bracket, just above fuel injection pump. Turn ignition on with engine off. Using DVOM, measure voltage between cylinder block and terminal No. 5 (Dark Blue/White wire) on APPS connector. If voltage is more than 4.5 volts, go to next step. If voltage is 4.5 volts or less, go to step 7.

[*]3. Turn ignition off. Ensure APPS connector is still disconnected. Measure resistance between terminal No. 4 (Black/Yellow wire) and terminal No. 5 (Dark Blue/White wire) on APPS connector. If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short between Dark Blue/White and Black/Yellow wires. The Black/Yellow wire is the sensor ground circuit.

[*]Ensure APPS connector is still disconnected. Disconnect ECM connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Measure resistance between ground and terminal No. 3 (Light Blue/Black wire) on APPS connector. If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short to ground in Light Blue/Black wire.

[*]Ensure APPS and ECM connectors are still disconnected. Measure resistance between ground and terminal No. 5 (Dark Blue/White wire) on APPS connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue/White wire.

[*]Turn ignition off. Ensure APPS connector is still disconnected. Reconnect ECM connector. Measure resistance between terminal No. 3 (Light Blue/Black wire) and terminal No. 4 (Black/Yellow wire) on APPS connector. If resistance is greater than 5 ohms, replace APPS. If resistance is 5 ohms or less, repair short between Light Blue/Black and Black/Yellow wire. The Black/Yellow wire is the sensor ground circuit.

[*]Ensure APPS connector is still disconnected. Disconnect ECM connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Using DVOM, measure resistance in Dark Blue/White wire between terminal No. 5 on APPS connector and terminal No. 31 on ECM connector. If resistance is less than 5 ohms, replace ECM. If resistance is 5 ohms or more, repair Dark Blue/White wire.

[*]Turn ignition off. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Measure resistance between cylinder block and terminal No. 23 (Orange/Dark Blue wire) on PCM connector C1. This is the APPS signal wire and goes to terminal No. 28 (Orange/Dark Blue wire) on ECM connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step 10 .

[*]Ensure PCM connectors are still disconnected. Disconnect ECM connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Measure resistance between cylinder block and terminal No. 23 (Orange/Dark Blue wire) on PCM connector C1. If resistance is less than 5 ohms, repair short to ground in Orange/Dark Blue wire between ECM and PCM. If resistance is 5 ohms or more, replace ECM.

[*]Ensure ECM connector is still disconnected. Reconnect PCM connectors. Measure resistance between terminal No. 28 (Orange/Dark Blue wire) on ECM connector. If resistance is 5 ohms or more, go to next step. If open short to ground exists, replace PCM.

[*]11. Ensure APPS and ECM connectors are still disconnected. Measure resistance in Orange/Dark Blue wire between terminal No. 28 on ECM connector and terminal No. 23 on PCM connector C1. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in open in Dark Blue/White wire between ECM and PCM.

[*]Ensure PCM connectors are still disconnected. Reconnect ECM connector. Turn ignition on with engine off. Using DVOM, measure voltage between cylinder block and terminal No. 23 (Orange/Dark Blue wire) on PCM connector C1. If voltage is more than .4 volt, replace PCM. If voltage is .4 volts or less, replace ECM.

[mrtowman4u]

I know this sounds crazy....but check your alternator. I would have the same problem and it was my alternator failing. Sent from my DROID RAZR using Tapatalk 2

[CSM]

Update: Replaced Timbos APPS. Alternator fine, all else fine, and I could feel the consistent drop in throttle at the same point in the pedal regardless of load/rpm/etc. WOW! Its like comparing a smoldering pine cone to Charmin! Smooth, high resolution sensor that makes my 47RE happy and shift better, even with the Edge and somewhat laggy turbo cruise control is silky smooth... I wish I had done this a long time ago.