for you guys with modern Hemi's find a dealer mechanic that knows what he is doing ....on this. and you should see an improovement in et/mph.
have him check and calibrate the TPS throttle position sensor... they are all over the place.

the timing curve is based off this.
and also check the range on the MAS..
oil consumption will cause detonation which will cause the ecu to dump ignition timing..
all three of these will kill 4 mph..
cheapst.