I stand by my mechanical view of the Hemi. Very good engine, few failures of any kind.
That said, and new information provided, I can provide you with a little more information, but positive answers require personal intervention.
Software was an early issue with the Hemi, being our first domestically-produced unit with drive-by-wire circuitry. Most issues were resolved by the 2005 year. You may want to check with your friendy local Dodge dealer for availablility of updates.
Lift throttle stalling could come from three sources.
- First, software. I really know of no updates to the PCM software that affects lift-throttle stalling. Admittedly (from the gurus at Dodge themselves), updates sometimes encompass more than they are billed for. An unrelated update may do more good than advertised. Still, nothing known for this condition.
- Crud buildup in the throttle body area. Original programming for airflow through the throttle body area does not provide for the inevitable buildup of crud as it accumulates in the blade/ bore area. This decreases airflow and might contribute to a lift-throttle shift-change event. Clean the crud off with a cloth (no solvent required), see what happens.
- Transmission issues. If the stall event can be reproduced, try to relate it to a manual transmission when the clutch is left out. A manual transmission-equipped vehicle will have stall issues if you leave the trans in gear and fail to push the clutch in at stops. This problem may feel similar.
- You may have to do several stops to reproduce this effect. When coming up to a stop, brake to around 5mph. Lift off the throttle and continue braking. Take it down to a single mph or so, feeling whether the engine is being dragged down by the vehicle speed. If the feeling is that the transmission is solid-locked to the wheels, the problem is with the trans. A trip to the Dodge Garage is then warranted.
There are too many variables for me to give you a definitive answer at this point. Use this guide for reference when talking to the repair facility so they may get to the root cause of your problem more quickly. At this point, I can't identify a reason why using higher octane fuel would be an issue, but include that in your complaint to the dealer.
I wish you luck. Barring that, a good driveability guy. Ed.