Disable AFM

[gundog]

Can anyone comment on the affect on gas mileage by disabling AFM (DOD) on either a 2007 Yukon or Tahoe with the 5.3 flex engine. Also is there any potential for damage to the engine if disabled long term?

[06MonteSS]

no potential damage... and is actually better for it... the DOD causes oil consumption by letting oil blow by.. there's a GM service bulletin out about it... people are seeing their vehicles use anywhere from 3/4 - 1.5 quarts of oil between oil changes.. and it's because of the DOD operation....

with the DOD disabled, it does not happen, because it's always in V8 mode and the lifters are not collapsing, etc etc...

i've had my DOD disabled in my car for 5.5 years... and have not had one single problem/issue...

my driving habit is 50/50 highway/town driving during the week for my work commute - 80 miles a day... and with my DOD disabled, I'm getting 20.8 mpg... if I turn it on, I lose mileage - I drop to about 18.5 mpg...

BUT, if you do a LOT of / mostly highway driving, then the DOD would benefit you by being on...

only way to really tell is to drive a few weeks with it off... then drive a few weeks with it on... and compare your mileage for your normal driving habits and see what's better for ya...

[black03silverado]

my 08 silverado 5.3 leveled with 33" tires, diablo tune 91 octane fuel on a 300mile run at 60-65 mph and got 21mpg!!!! averaged 18mpg all weekend trip of around 800miles!! and my truck works awesome mind you if you drive it hard it likes it's fuel ALOT,but thats to be expected hope this helps