2013 Yukon 6.2 Engine Performance

[TruckME]

Hi guys,

I have two questions about my 2013 Yukon 6.2L. The car is working just fine but there are two things that I am not sure how normal they are.

1. The car feels a bit sluggish at lower speeds of upto about 40 MPH. When I push the accelerator the car doesn't feel like it is picking up speed fast enough and the transmission seems to have delayed shifting. At speeds higher than 40 MPH the accelerator seems more responsive and car seems to have more power. I have learned to listen to the engine when accelarting and push the car gradually until it picks up speed. But not sure if this is the way it is supposed to be.

2. When I accelerate really hard, the engine "gasps" for air. It definitely doesn't feel right. and when I lift my foot a bit from the accelerator, the engine starts working fine again. Again I have learned to listen to the engine and accelerate accordingly without causing the issue.

Are these issues related to the throttle body. If yes how can I fix it?

Thanks in advance.

 

[B-train]

After dealing with a similar issue, I would lean towards the fuel pump. I found that the pump is a great design........the non-serviceable filter is a PLANNED failure point. A tank or 2 of bad, dirty gas, will plug it up.

My truck was gasping for air in MT on a road trip after filling with premium fuel (obviously they didn't move much fuel and I helped clean out the lines). I could barely accelerate, but I nursed it along and eventually made it home using lighter throttle input. Mountain passes were definitely slower than planned.

Funny thing is that I put in an access door before the trip and had a new fuel pump with me just for "what if, the truck has 200k on it." I opted to not get stuck needing some random part in the middle of a national forest and limped it back home. In hind sight, after replacement the very next day, it would've been easy to do on the road with an extra set of hands and the tools we had present. Sorry, long winded......

Here's what a filter for life looks like after 202k miles - and 1 or 2 tanks of questionable fuel quality. The black fluid is what flowed backwards out of the filter inlet.......it did its job because the outlet fuel was clean. Flow definitely restricted.

 

[TruckME]

After dealing with a similar issue, I would lean towards the fuel pump. I found that the pump is a great design........the non-serviceable filter is a PLANNED failure point. A tank or 2 of bad, dirty gas, will plug it up.

My truck was gasping for air in MT on a road trip after filling with premium fuel (obviously they didn't move much fuel and I helped clean out the lines). I could barely accelerate, but I nursed it along and eventually made it home using lighter throttle input. Mountain passes were definitely slower than planned.

Funny thing is that I put in an access door before the trip and had a new fuel pump with me just for "what if, the truck has 200k on it." I opted to not get stuck needing some random part in the middle of a national forest and limped it back home. In hind sight, after replacement the very next day, it would've been easy to do on the road with an extra set of hands and the tools we had present. Sorry, long winded......

Here's what a filter for life looks like after 202k miles - and 1 or 2 tanks of questionable fuel quality. The black fluid is what flowed backwards out of the filter inlet.......it did its job because the outlet fuel was clean. Flow definitely restricted.

Interesting. Thanks for the comment. The fuel had not cross my mind. I will do some research on that. And good call for driving around with an extra fuel pump

 

[Fless]

Rent a fuel pressure gauge kit from your local auto parts store and test that fuel pressure.

 

[B-train]

I had good fuel pressure on mine, which was the strange part, just not enough flow. I'm not 100% sure where the fuel pressue is measured on this engine, because it was always within spec when it was laboring to supply the engine. A new fuel pump and it feels like a brand new truck!

 

[swathdiver]

Hi guys,

I have two questions about my 2013 Yukon 6.2L. The car is working just fine but there are two things that I am not sure how normal they are.

1. The car feels a bit sluggish at lower speeds of upto about 40 MPH. When I push the accelerator the car doesn't feel like it is picking up speed fast enough and the transmission seems to have delayed shifting. At speeds higher than 40 MPH the accelerator seems more responsive and car seems to have more power. I have learned to listen to the engine when accelarting and push the car gradually until it picks up speed. But not sure if this is the way it is supposed to be.

2. When I accelerate really hard, the engine "gasps" for air. It definitely doesn't feel right. and when I lift my foot a bit from the accelerator, the engine starts working fine again. Again I have learned to listen to the engine and accelerate accordingly without causing the issue.

Are these issues related to the throttle body. If yes how can I fix it?

Thanks in advance.

There's programming called Torque Management that limits power in certain situations to prolong the life of the drivetrain.

Before spending a nickel on parts, I would suggest getting an ODBII adapter and pair it up with an app on your phone and start looking at the gauges to see if anything is amiss.

Fuel pressure ought to always be 43.5 psi give or take a pound at WOT. Look for knock retard, check your Long Term Fuel Trims, Check your alcohol content, see that your oxygen sensors are performing as expected and have not gotten lazy. They get lazy after around 100K miles and begin to miscalculate the alcohol content after that many miles.

The computer system does not take kindly to aftermarket parts. If you want maximum performance and as few gremlins as possible, run GM OE parts, especially the oxygen sensors.

The 6.2 can benefit from a larger air filter and cold air intake but I wouldn't install one until the engine and transmission was tuned.

Compare this data to what's stated in the shop manual to make sure everything is working optimally.

This is what I would do if yours was mine. Then, if all looked ok and she has an air filter with more than 20K miles and original spark plugs and wires, I would start replacing those parts incrementally and measuring performance. Air filter, then plugs, then wires, GM OE only. Then fluids, then tune, etc.

 

[Marky Dissod]

There's programming called Torque Management that limits power in certain situations to prolong the life of the drivetrain.
Before spending a nickel on parts, I would suggest getting an ODBII adapter and pair it up with an app on your phone
and start looking at the gauges to see if anything is amiss.

Fuel pressure ought to always be 43.5 psi give or take a pound at WOT.
Look for knock retard, check your Long Term Fuel Trims, Check your alcohol content, see that your oxygen sensors are performing as expected
and have not gotten lazy. They get lazy after around 100K miles and begin to miscalculate the alcohol content after that many miles.

The computer system does not take kindly to aftermarket parts.
If you want maximum performance and as few gremlins as possible, run GM OE parts, especially the oxygen sensors.
The 6.2L can benefit from a larger air filter and cold air intake but I wouldn't install one until the engine and transmission was tuned.

Compare this data to what's stated in the shop manual to make sure everything is working optimally.

This is what I would do if yours was mine. Then, if all looked ok and she has an air filter with more than 20K miles and original spark plugs and wires,
I would start replacing those parts incrementally and measuring performance. Air filter, then plugs, then wires, GM OE only. Then fluids, then tune, etc.

You WILL be pleasantly surprised by what happens after the tune.

And there can only be one Ol Dirty Basdart (guess we're all children here?).

 

[TruckME]

There's programming called Torque Management that limits power in certain situations to prolong the life of the drivetrain.

Before spending a nickel on parts, I would suggest getting an ODBII adapter and pair it up with an app on your phone and start looking at the gauges to see if anything is amiss.

Fuel pressure ought to always be 43.5 psi give or take a pound at WOT. Look for knock retard, check your Long Term Fuel Trims, Check your alcohol content, see that your oxygen sensors are performing as expected and have not gotten lazy. They get lazy after around 100K miles and begin to miscalculate the alcohol content after that many miles.

The computer system does not take kindly to aftermarket parts. If you want maximum performance and as few gremlins as possible, run GM OE parts, especially the oxygen sensors.

The 6.2 can benefit from a larger air filter and cold air intake but I wouldn't install one until the engine and transmission was tuned.

Compare this data to what's stated in the shop manual to make sure everything is working optimally.

This is what I would do if yours was mine. Then, if all looked ok and she has an air filter with more than 20K miles and original spark plugs and wires, I would start replacing those parts incrementally and measuring performance. Air filter, then plugs, then wires, GM OE only. Then fluids, then tune, etc.

Okay, that's a good to-do-list for me. Thanks for taking the time to write this up.

 

[B-train]

Have you ended up with any concrete fixes at this time? If so, what did you do and how has it changed the driveability?

 

[TruckME]

Have you ended up with any concrete fixes at this time? If so, what did you do and how has it changed the driveability?

Thanks for the follow-up. I kept forgetting to give you all an update here. I have found the problem but still need to fix it.

Here is an update:
First, I ran a diagnostic test with a relatively decent OBDII reader. Everything looked okay, so I suspected it must be something related to a piece that doesn't have any sensors.
Another thing that happened just by chance is that my engine stalled once. It did it after a few seconds of running. I read about this issue and it seems that it is usually related to the fuel pump.
Then I took the truck to a mechanic and asked to check the fuel pressure and sure enough it was quiet low.

Now, the truck is still running fine, it just doesn't have as much power when accelerating at lower speeds. At higher speeds, it is still functioning well. I guess there is also some performance drop at higher speed but I can't really tell.
Next, I need to find some time to replace the pump and the filter. Once done, I will update here again.

Thanks all for your comments. With the help of you guys on this forum, I can keep my truck for many more years