This is what I'm wondering. Can MDS be deactivated with a tuner? I've been on enough flat roads and feathering the pedal and no light comes on. Avg mpg is 17.5 on my 50mi rountrip commute which is 50/50 back roads and highway. I knew I'd take a hit on mpg compared to my Ranger, but not this bad. Love the truck though. If it costs $500 more a year in fuel, I'm ok with that, but would still like the benefit of Econ
Also saw this online: "You may also want to disable the MDS on your vehicle if you use aftermarket exhaust. This is because of the goofy sound it produces when the engine switches from eight cylinders to four cylinders."