I think it started in '05. I have an '05 Jeep w/ Hemi and it shuts cylinders off as well. Only problem is if most of your driving is 'round town you're always running on all 8. I have to agree with Mac, though. I got a lot of power, but I expected more outa a Hemi than what it is... Especially considering the average of 11 mpg I get while driving around town :o. That thing gulps gas just sitting at a red light! Stand on the gas for a quick take off and it'll cost ya 5 buck for every 100 yards! ;D Howerever, with cruise set around 65 I get 20-21 mpg. At 75 I get between 18-19mpg. Anything faster than that and milage goes downhill pretty quick.