DFM yes or no

[RSTJohn]

Is there a way to do a survey of 5.3 owners that just let DFM work as designed compared to those that delete DFM one way or another?

[KARNUT]

1 hour ago, RSTJohn said:

Is there a way to do a survey of 5.3 owners that just let DFM work as designed compared to those that delete DFM one way or another?

It’s been done on older cylinder deactivation models. In my case on an older vehicle at 70 mph. There wasn’t enough difference to register. Of course there’s outliers. Some doing low speed testing claim some difference. If you look one some new truck stickers or information the claim is 1 mile per gallon. 

Edited August 15, 2022 by KARNUT

[mafd2]

My 2019 RST had DFM and my '22 LTZ Z71 doesn't and I'm glad.

[Byrds8]

I turned mine off. I never have liked DFM or AFM.

[Bikerjon]

My 2021 Trail Boss Custom did not have DFM or Auto Start but if it did I would definitely disable it. There has been a lot of problems associated with DFM.

[Z45]

According to GM:

    Internal components related to AFM or DFM function will be present in engines; wiring, connectors, and fuses will be present in vehicles with RPO YK9. The ECM will not be capable of activating the cylinder deactivation technology.

    When diagnosing and repairing concerns with base engine or electrical function which may be related to AFM or DFM related hardware; utilize appropriate diagnostics within SI and replace any needed components as directed by the Electronic Parts Catalog; no changes will occur to AFM or DFM related components.

    Important: Any truck designated with RPO YK9 CANNOT be reprogrammed and changed to “Turn on” the AFM/DFM functionality.

[RetCPO]

2020 AT4 5.3 w/dfm. I always drive in L9 dfm won't engage, but I do lose 10th gear.

I'd rather have 8cyl all the time. Not sure what the mpg loss is on the highway but I'm not worried about it.

[CamGTP]

My parents have a 2021 5.3 with DFM, I've driven it many times and towed with it several times and I can barely notice the DFM working. The AFM trucks are alot more noticeable if you ask me. It's only got like 5,000 miles on the truck and it's been problem free.

[2020RSTBorla]

I recently added the Pulsar LT.

 

I was getting a mild shudder in certain situations and it was concerning.  Since turning off DFM it has completely disappeared and imo the shifting is much improved.

 

I have the throttle sensitivity set to 3 and I love it!  It took a few days to get used to the new throttle response.  Like when you drive a car that has a sensitive brake pedal and you are used to a more mushy brake pedal.  

 

Turning off Auto start/stop is also a great thing.  Still getting used to not having to turn it off.

 

This thread is about DFM, but I love the Pulsar LT and I love not having DFM on anymore.  It is very noticeable, at least to me.  I have a Borla Touring cat back exhaust with S&B cai.

[BossTaco2020]

2020 TrailBoss LT w/5.3 & DFM. I never notice it and haven't tried to disable it. 37K miles and running like I bought her yesterday.

[Street Queen]

Going from a 2019 Silverado with DFM to a 2022 Refresh TB W/O DFM, I definitely like not having DFM.  If you can snag one w/o DFM I recommend pulling the trigger ASAP B4 DFM is standard again.