My understanding of the GM 5.3L or 6.2L with the Active Fuel Management (or other names of similar systems) is that they have been very problematic. Is that still true on the direct injected engines 2015 and up? If so, is there a way to make them reliable ie permanently shut off that system? I will be looking for a later model Silverado or Sierra soon, probably 2015-2020 range and would rather avoid problems. Is the direct injection an issue with these engines ie intake valve deposits or serious fuel dilution or have they figured a way to avoid that without regular cleanings and oil changes?