Duramax started idleing high. Anyone know why?

[sea trout]

Hello fine folks!!
My wife drives our 2016 Duramax GMC, it has 50k miles on it now.
She told me that yesterday it started idleing high all day.
When she was creeping ahead in the line at school to pick up the kids.....she said when she took foot off the break the truck would lunge forward. And with her foot on the brake the idle was high.
I searched youtube for a similar problem and all I can find are people who are doing it intentionally for a faster cold morning warm up.
The truck goes to dealership Wed anyway for new tires and new fuel filter. So I'll mention it there too.
But just wondering if y'all knew what's up with it.
Thanks y'all!!!!

 

[GoldDot40]

Make sure the floor mat isn't partially covering the throttle pedal. You laugh...but I've seen it.

 

[georgia357]

Make sure the floor mat isn't partially covering the throttle pedal. You laugh...but I've seen it.

I've seen this before too, probably be surprised at the number of times it happens.

 

[1gr8bldr]

Running a def cycle. It's cleaning the oven, so to speak. The exhaust will be dangerous hot when it does this. Sometimes you never know it because the computer triggers the cycle when your going down the road. It sends the def fluid into the exhaust system, burn everything to ash and blows it out,

 

[sea trout]

Thanks! Great info for us to know!
She called before noon and said she ran up I-85 to Lavonia.....she stopped for fuel and after she restarted the engine to leave the station the duramax idled back down to normal.

 

[1gr8bldr]

My 2015 eventually gave me problems. The computer quit communicating with the def system. It kept telling me to add.... or else, the speed minimum punishment. LOL, it was full. I got all the way to the 4 mph punishment. I researched the issue. Only the dealerships will touch it. And they will have a 20% chance of throwing the right part or sensor at it, so they, all of them, replace everything at the cost of over $4000. So I had mine deleted. Straight piped, tuned with 4 settings to choose from, and now it's like a race car and averages 5 mpg better everywhere, and gets 22 mpg at 80 mph. And this cost me $1400. It has saved me that much in fuel already, plus saving me the $4000 And did I say "like a race car"! 80 mph on the freeway and hit the foot pedal and it's like it's electric. It just takes off like an airplane

 

[GoldDot40]

Yep, most towing companies will tell you. Best thing that ever happened for them is when the EPA started making manufacturers put diesel particulate filters on every diesel engine. Big rigs are no different.

 

[sea trout]

My 2015 eventually gave me problems. The computer quit communicating with the def system. It kept telling me to add.... or else, the speed minimum punishment. LOL, it was full. I got all the way to the 4 mph punishment. I researched the issue. Only the dealerships will touch it. And they will have a 20% chance of throwing the right part or sensor at it, so they, all of them, replace everything at the cost of over $4000. So I had mine deleted. Straight piped, tuned with 4 settings to choose from, and now it's like a race car and averages 5 mpg better everywhere, and gets 22 mpg at 80 mph. And this cost me $1400. It has saved me that much in fuel already, plus saving me the $4000 And did I say "like a race car"! 80 mph on the freeway and hit the foot pedal and it's like it's electric. It just takes off like an airplane

Very nice!!!
We want to have that done to ours also after warranty runs out.
Where did you get yours done, any where around north east Ga??
Sounds like you're very happy with the delete. I've heard 2 other people who had the delete and reprogramming and they're very happy too.

 

[1gr8bldr]

Very nice!!!
We want to have that done to ours also after warranty runs out.
Where did you get yours done, any where around north east Ga??
Sounds like you're very happy with the delete. I've heard 2 other people who had the delete and reprogramming and they're very happy too.

I am in NC, but if your still interested, let me know

 

[3ringer]

Join the Duramax forum on FB. There are thousands of Duramax owners on there. I belong to about 20 different forums .