GM Truck Club
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Page 2 of 2 FirstFirst 12
Results 11 to 13 of 13
  1. #11


    Quote Originally Posted by bachus View Post
    2007 GMC Sierra extenda cab half ton 4 wheel drive SLT. I have the 5.3 AFM find the MPG is decent but do not like the oil consumption that started around 58000 mile It now ha app 68000 mile on it and uses two quarts every 3000 mile which is when the oil gets changed. From doing research they blame it on the AFM. Hope this is something that GM can solve.
    2 qts every 3k is a lot of oil, does it leave spots or smoke? I mean wheres the oil going, there should be some signs of that.
    I cant see how the AFM would cause it to use more oil, even if the cyinders are shut down they shouldnt be leaking oil past the rings or valves. From my understanding the shutdown cylinders are still open via the valves and pushing air through the cylinders but they dont have fuel or fire to complete a combustion cycle, they arent necessarily building compression but then again compression isnt what causes the oil to be wiped off the cylinder walls, thats what the rings do. I think I'd have to push this issue with GM a little further something doesnt sound right.

  2. #12


    Quote Originally Posted by KWG08VMI View Post

    I would definitely say that the 5.3L is worth the money. Especially if it has the AFM. I have a 2010 1500 with the AFM on it and I love it. I average 19.5 mpg during the week and about 18 on the weekends running around town. Coreyallen is correct, if your Driver Information Center (DIC) displays all of the information it will tell you if the motor is in 4 or 8 cylinder mode. I didn't get all of the options on my truck so my DIC doesn't tell me when it's in 4 cyl. mode.
    I see you have a 2" leveling kit... what size tires do you have? I have NEVER got 19 on my truck. (2010 1500 4x4 5.3 6 spd 3.08) I was getting 17.6 and when I put the 285's on it dropped big time

  3. #13
    Sr. Apprentice
    Join Date
    Jul 2011
    Mississauga, Ontario, Canada


    I just bought a used 2010 Sierra with the 5.3/6 speed combo. In the city, I seem to be getting 18L/100km. That's a far cry from the sticker that stated it should get 14.4L/100 km in the city. The previous owner had 18" wheels on it (Bridgestone Dueler Tires). Would I see an improvement in the mpg if I went to 17" wheels?

Page 2 of 2 FirstFirst 12

Similar Threads

  1. Starting Research on New Mud Tires
    By ippielb in forum Wheels & Tires
    Replies: 12
    Last: 04-23-2011, 09:14 AM
  2. Starting Research on New Mud Tires
    By ippielb in forum Wheels & Tires
    Replies: 12
    Last: 04-23-2011, 09:14 AM
  3. Replies: 0
    Last: 10-10-2009, 04:10 PM
  4. Replies: 0
    Last: 12-22-2007, 10:29 PM
  5. Research Project..i need help please
    By mr.copenhagen in forum Chevy C/K Truck Forum
    Replies: 13
    Last: 04-23-2007, 11:20 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts