Questions about GMC Sierra's

[Maverickpro201]

I have a few questions
Looking at possible going back to a Gas burner. Looking at used 2017 up. What should I know about these GMC Sierra's 1500's?
What kind of MPG do you get with one.?
I have not owned a Gas Burner since 1989. Always a Dodge Cummins, 2500 and 3500's. 1990, 1994, 1998, 2003, and now 2012 1/2. Just do not tow heavy like I use too.
All help appreciated
Thanks.

[Dutch]

I have a Chevy that is quite similar to the GMC Sierra.  It is a 2020 Silverado Z21 LTZ.  I did a lot of research after selling my 5th wheeler because I was going to continue pulling my glitter sled.  I’ve never had a high speed rear end and didn’t know about that or a 5 liter engine.  I finally talked to a couple of service techs whom I trust.  Both told me that it would do fine even though my rig is approaching 5000 lbs.

 It has plenty of power to top these Ozark hills to and from the lake.  Mileage wise I get over 20 mpg on the highway, sometimes as much  as 24.  Pulling my boat it fluctuates from 13 to 14 mpg depending on which lake.

[gotmuddy]

If you buy one be dang sure you get some kind of warranty.  The 5.3 engine has a terrible track record unless you program away the AFM lifters, and the 6l80e transmission is trash. the 8l90e is better.

[snagged in outlet 3]

WIDESPREAD LIFTER FAILURE!! MANUFACTURING DEFECTS AND DENIAL!

You should google Active Fuel Management before you buy one.  Ram has it too.  And don't AFM delete or you lose the warranty.  Ford does not use that in the coyote.

[Dutch]

So I guess I got lucky.  I’d buy it again tomorrow if I needed a new truck.

[MrGiggles]

Get the 6.2/8L90 combo and disable the AFM. 

I used to be a pretty big GM guy but some of their engine designers need to be fired with the crap they've made recently. The new 5.3s, 3.6, 2.4, all turds. Ford is eating their lunch with the 6.2, 7.3, and Ecoboosts.

[nomolites]

I have had no issues with my ‘18, but I am still low mileage.  Pulls better and has better fuel economy than my ‘96.

Unfortunately, in many cases newer is not better.  I hope I’m a lucky one like Dutch.

Mike

[snagged in outlet 3]

For fair disclosure I have a Ram AFM and have 158K miles with no issues.  Knock on wood.  On the Ram tow/haul mode disables it.

[Maverickpro201]

What does AFM stand for? 

I know nothing!!!!!!!!!!!

[snagged in outlet 3]

10 minutes ago, Maverickpro201 said:

What does AFM stand for? 

I know nothing!!!!!!!!!!!

Active Fuel Management.  Shuts down 4 cylinders to conserve fuel when the power is not needed.