Did you ever lose power to the PCM prior to this behavior? Symptoms kind of sound like the TPS re-learn after battery replacement. You might try this:
Clear the PCM adaptive memory
1) Disconnect the negative battery terminal.
2) Run a jumper wire from the positive battery cable to the now disconnected negative battery cable terminal. NOTE. Do this with the negative cable DISCONNECTED from the battery. The short circuit you’re creating here is designed to drain all power from the capacitors inside the PCM. Leave the jumper connected for about 2-mins.
3) Reconnect the negative battery cable to the battery.
Turn off all electrical accessories before proceeding. Turn off headlights, blower motor, radio, wipers, etc.
4) Turn the key to run and wait for all warning lights to turn off. During the period the PCM will command the throttle body plate to sweep from full open to full close to “learn” the new positions.
5) Start the engine and let it idle for a full 10-mins until it reaches full operating temperature. During this period the idle may be higher than normal. It should slowly drop as the engine heats up. Watch the engine temp gauge and note when it reaches operating temp. Then continue to let it idle for an additional 5 minutes. It will continue to adjust idle during this period.
6) Drive the vehicle at various speed so the PCM learns shift points.
John, Lorie, Franklin, Sammi, Tina
2009 Dodge Ram 2500 6.7l Cummins G56
2020 Rockwood Ultra Lite 2912BS