GM Truck Club
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Page 1 of 2 12 Last Post byLast Post by
Results 1 to 10 of 13
  1. #1

    Default More 5.3L Engine Research

    I'm still continuing the research and pricing for a Sierra 1/2 ton W/T and I'm leaning towards the 5.3L engine. I'd like members opnions on this engine since it is an $1,770 option. Also, how do folks like the AFM feature of the engine? Finally, how can you tell when you are in the AFM mode? Is there some kind of indicator/signal or what?

  2. #2
    Sr. Apprentice
    Join Date
    Sep 2010
    Black River Falls, Wisconsin, United States


    So far with our 09 silverado its alright its right in the driver information center when you have the instant fuel eco on. I think some one else will chime in Im sure and correct me
    My truck doesnt accecpt donations it drinks em

  3. #3



    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.
    2002 Chevy 1500 Ex-cab Z71: 5.3L, auto 4, shorties, hi-flow cats, true dual 2.5" straight pipes, AirAid intake, TBS, Platinum plugs, 8.5mm wires, programmer, 3in w/ 33s, also has the composite bed

    2010 GMC 1500 Crew Cab Z71 w/ All Terrain package: 5.3L, auto 6, 2" Zone leveling kit, AirAid Jr. Intake Kit

  4. #4


    Thank you for the information. It helps in making a decesion. And ,yes, I'm strongly cosidering the 5.3L.

  5. #5
    Sr. Mechanic 747's Avatar
    Join Date
    Nov 2011
    Jackson, TN


    The 5.3 is totally worth the money, especially if you get the 6 speed transmission with it. We have two Silverados with AFM and it works seamlessly on both of them.
    2011 Silverado, ext cab, LT, Z71, 4X4, leather interior, color matched mirror caps & bowtie.

  6. #6
    Master Mechanic
    AMac's Avatar
    Join Date
    Feb 2012
    New England


    I had an '09 Sierra with a 5.3 and the AFM and was getting about 18-19 MPGs. In my new beast, '11 Silverado 5.3 w/ AFM I can barely get 15. I'm anxious to find out if it's because of the cap; I still have oem wheels so why such a difference, I don't know.

    What was the other engine option you were considering?

  7. #7


    AMac - I was looking at the 4.8L. But when I thought abaout the mods I would add, I'd end up (probably) with a 4.8L that performed like a 5.3L. And if I end up with the 5.3L I'm planning on addding mods.

  8. #8


    I would have to agree with everyone else that the 5.3 is worth the money.

    2008 Ext. Cab Silverado LT1 5.3L 2WD
    APC LED Tail Lights | Spec D Smoked Third LED Brake Light | aFe Magnum Force Stage 2 CAI

  9. #9


    If your still searching for a Silverado with a 5.3/6 spd look for one with the "All Star" package, the package runs a little under $2000 but includes the 5.3/6 spd combo and a few other nice to have extras like Blue Tooth, Power Drivers seat, trailering pkg, and additional extras I'm forgetting.
    The 5.3 definately has a few extra ponies over the 4.8 and with the 6spd auto the MPG is slightly better than the 4.8.
    5.3 equipped trucks with 20" wheels seem to be averaging a few MPG less than those with the 18" wheels.
    There have been some complaints of thunking from the transmission during downshifts from 6-5 and 2-1, but overall the transmission shifts smooth.
    One issue with the 5.3 and AFM I dont particularly care for is the fact that GM has made it extremely hard to modify anything on the drivetrain unless you get the computer tuned after the change. Changing an item as simple as the muffler can lead to erratic shift patterns of the transmission and stop the AFM from cycling to the 4 cyl mode.
    Some tuners have made it possible to turn off the AFM and those that have went this route report no loss of MPG.
    Overall its a great choice for an engine trans package.

  10. #10


    I have a 2007 GMC Sierra extenda cab half ton 4 wheel drive SLT. I like the truck, has a few squeeks but am taking care of one by one. 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. Very disapointed with that but only have a couple payments left so I guess I am stuck with it. I have Ford in the past put over 125000 miles on and never added oil. Hope this is something that GM can solve. I really didn't want to start the paymeny club again. Gonna retire in two years.

Page 1 of 2 12 Last Post byLast Post by

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