AFM mode issue

luapxix · November 28, 2016

I have a 2015 5.3 SLE with 6000 no issues so far but last time i was on the freeway the truck struggled with dropping into V4 mode. around 70mph it would drop in and out of V4 to V8 when in cruise control.

Has anyone else had these issues?

I also have the factory borla and the MIT tube would this cause this issue?

luapxix · November 28, 2016

to be a little more descriptive when cruising on the freeway the truck is smooth i cant feel a difference but on the screen that shows MPG it switches from V4 to V8 while in cruise control back and forth really fast like it cant decide and the MPG indicator will jump from 18 to upper 26's back and forth.

Dnt · November 28, 2016

Could be any number of things like - NORMAL for cruise control / a tank of bad fuel / using Auto 4whl drive mode / Low tire pressure / Strong headwind / Operator needs a 6.2 etc. So what all have you checked so far? TURN OFF cruise control and manually drive to see if problem persists / Go get a tank of Tier1 93 octane / check to be sure you are in 2 whl drive mode / check for windy conditions / check tire pressure / go trade for a 6.2 8spd truck immediately.

Note: cruise control kind of sucs it depresses the gas pedal more than I would if I were driving conservatively to save fuel. It is a compromise especially with a 5.3 engine unlike a 6.2 where the excess HP and Torgue can keep it in V4 even up a fairly steep grade. You probably just need a new truck with a more powerful engine. haha

luapxix · November 28, 2016

Good points I'll check gas tire psi etx. It only does it in cruise control and works fine when I have my foot on the pedal and ease up.

I don't really want a 6.2 don't want to settle have my mind set on z28

Sean Neilan · November 28, 2016

I've noticed at 65 my 2015 5.3 will stay in V4 a lot, but at 70 mine does as your does. Basically any time it's not coasting or near level, it will switch back into v8 to maintain speed. So when you get those little dips it switches to V4 and then right back into v8. Normal operation albeit slightly annoying.

Slugworth · November 28, 2016

I've noticed at 65 my 2015 5.3 will stay in V4 a lot, but at 70 mine does as your does. Basically any time it's not coasting or near level, it will switch back into v8 to maintain speed. So when you get those little dips it switches to V4 and then right back into v8. Normal operation albeit slightly annoying.

How do you k ow when your truck is in V 4 mode??

nluchau · November 28, 2016

How do you k ow when your truck is in V 4 mode??

Look at your fuel economy screen on your dash.

http://gas2.org/wp-content/uploads/2014/07/2014-Chevy-Tahoe_07.jpg

Sean Neilan · November 28, 2016

How do you k ow when your truck is in V 4 mode??

In the DIC screen on the fuel economy or trip odometer screens it will have a green V4 or red V8 icon in the bottom right corner depending on what mode it is in.

Slugworth · November 28, 2016

Look at your fuel economy screen on your dash.

http://gas2.org/wp-content/uploads/2014/07/2014-Chevy-Tahoe_07.jpg

In the DIC screen on the fuel economy or trip odometer screens it will have a green V4 or red V8 icon in the bottom right corner depending on what mode it is in.

I have a 2011 1500 so my dash doesn't have the screen like that.

Sean Neilan · November 28, 2016

I have a 2011 1500 so my dash doesn't have the screen like that.

Than I have no idea. I have a 2015.

Slugworth · November 28, 2016

Than I have no idea. I have a 2015.

Thanks.

luapxix · November 28, 2016

Thanks for the info I was just curious if it was just my truck

I've noticed at 65 my 2015 5.3 will stay in V4 a lot, but at 70 mine does as your does. Basically any time it's not coasting or near level, it will switch back into v8 to maintain speed. So when you get those little dips it switches to V4 and then right back into v8. Normal operation albeit slightly annoying.

gSwift · November 28, 2016

Thanks.

Just to be sure, but you do know you're in the 2014+ section right? A lot of the things here don't apply to your generation truck

Rally216 · November 28, 2016

Could be any number of things like - NORMAL for cruise control / a tank of bad fuel / using Auto 4whl drive mode / Low tire pressure / Strong headwind / Operator needs a 6.2 etc. So what all have you checked so far? TURN OFF cruise control and manually drive to see if problem persists / Go get a tank of Tier1 93 octane / check to be sure you are in 2 whl drive mode / check for windy conditions / check tire pressure / go trade for a 6.2 8spd truck immediately.

Note: cruise control kind of sucs it depresses the gas pedal more than I would if I were driving conservatively to save fuel. It is a compromise especially with a 5.3 engine unlike a 6.2 where the excess HP and Torgue can keep it in V4 even up a fairly steep grade. You probably just need a new truck with a more powerful engine. haha

Tool.