I have never had much luck with cylinder deactivation in Full-Sized, V-6 cars: Impala, Monte Carlo. 3-cylinder mode (as indicated by the dash indicator) would hang on until the load built-up and cycled back into 6-cylinder mode. On the highway, this was quite cyclical at 65-70 mph and didn't show much gain at all in FE. Some engines were Flex-Fuel equipped, and allowed better performance of the AFM system with E85, but was entirely subtracted by the poor FE of E85.
(For the record, GM's "
Active Fuel Management" is a mechanical process of manipulating valves -- it cannot be programmed if not equipped".
55-60 mph seemed to be ideal. The wind resistance was light enough to keep the load figures down and keep it locked-in as a 3-banger. Suburban-enviroment FE improved as well (~45 mph).
So, the trick with the pickup might be to monitor the load and figure out the parameters that it locks/unlocks. IIRC, the Imp factored a load of ~50-51% and full TC lockup. Reduce this through technique or mods could get you that elusive 30 mpg with the pickup.
-RH77