2017 Yukon hesitating/shuddering

[Td_symmons]

Hi all! New to the forum and first post:

I have a 2017 GMC Yukon 5.3 SLE 4WD (157k miles) with a hesitation issue. While accelerating, the vehicle experiences a slight shudder and acts like it has a very hard time accelerating until it downshifts and the shudder goes away. No trouble codes. Shudder/shake does not persist after letting off the gas pedal. No matter the speed (but it’s worse at highway speeds). The following maintenance was just completed about 1k miles ago to fix other issues- after which this new problem arose.

-New full set of OEM (nominal flow) injectors
-Intake port cleaning
-Tire rotate & balance
-Added some Lubegard platinum to the transmission fluid

Important info:
-Transmission rebuild at 130k miles
-Spark plugs replaced at 130k miles

This really acts like a low fuel pressure problem from experience diagnosing other vehicles, but I am not really sure.

I have attached an image of my most recent graph recording of some PIDs while this issue occurred. Note the circled area since the screenshot was taken while the problem was recreated.

Anybody else have this issue or know what to check for? I included the MAP sensor reading on the graph since I saw one person with this issue reported a faulty MAP sensor being the issue.

 

[Joseph Garcia]

@NickTransmissions , just to be sure that your issue in not related to your rebuilt transmission.

 

[Td_symmons]

Hi! I’m really not sure about it being the transmission. I went for a test drive monitoring torque converter slip and froze the data when I experienced it. Here’s some screenshots. Note the data values above the graph.

 

[NickTransmissions]

Hi all! New to the forum and first post:

I have a 2017 GMC Yukon 5.3 SLE 4WD (157k miles) with a hesitation issue. While accelerating, the vehicle experiences a slight shudder and acts like it has a very hard time accelerating until it downshifts and the shudder goes away. No trouble codes. Shudder/shake does not persist after letting off the gas pedal. No matter the speed (but it’s worse at highway speeds). The following maintenance was just completed about 1k miles ago to fix other issues- after which this new problem arose.

-New full set of OEM (nominal flow) injectors
-Intake port cleaning
-Tire rotate & balance
-Added some Lubegard platinum to the transmission fluid

Important info:
-Transmission rebuild at 130k miles
-Spark plugs replaced at 130k miles

This really acts like a low fuel pressure problem from experience diagnosing other vehicles, but I am not really sure.

I have attached an image of my most recent graph recording of some PIDs while this issue occurred. Note the circled area since the screenshot was taken while the problem was recreated.

Anybody else have this issue or know what to check for? I included the MAP sensor reading on the graph since I saw one person with this issue reported a faulty MAP sensor being the issue.

Those graphs show the TCC is behaving as expected, so whatever is causing your shudder/vibrations it's not the torque converter clutch and/or TCC electro-mechanical circuitry. If it was, your slip speed would be much higher than it's reading and the graphs would look completely different.

That said, it is interesting that the shudder goes away once you downshift.

- Is this pattern constant or intermittent?

- How does the vehicle feel power-wise when you take off from a stop?

- Have you checked your fuel pressure? If so what is it?

- Lastly, what transmission do you have? 6L80 or 8-speed (thinking you should have a 6L80 but will let you confirm/deny).

 

[Td_symmons]

Those graphs show the TCC is behaving as expected, so whatever is causing your shudder/vibrations it's not the torque converter clutch and/or TCC electro-mechanical circuitry. If it was, your slip speed would be much higher than it's reading and the graphs would look completely different.

That said, it is interesting that the shudder goes away once you downshift.

- Is this pattern constant or intermittent?

- How does the vehicle feel power-wise when you take off from a stop?

- Have you checked your fuel pressure? If so what is it?

- Lastly, what transmission do you have? 6L80 or 8-speed (thinking you should have a 6L80 but will let you confirm/deny).

Absolutely. It is very consistent. Any time I’m going about 70mph and press the gas pedal a bit harder, it will recreate the problem almost every time. Let go of the gas pedal, and it stops- and drives smoothly. It’ll also do it on cruise control under the same conditions.
When I take off from a stop, it feels just fine really. It’ll take off without a problem and speed up. I may have said “any speed” in my first post but it’s really only in highway speeds. I can’t really get it to happen much under 60mph. It’s quite noticeable though. After I did a full injector set replacement, I noticed the problem on my test drive. Went and got rotate and balance to make sure.
In my first post I included a pic monitoring fuel pressure. I’ll attach another one here, showing the freeze frame values at the top when the issue repeated. I have a 6L80. Thank you

 

[NickTransmissions]

Absolutely. It is very consistent. Any time I’m going about 70mph and press the gas pedal a bit harder, it will recreate the problem almost every time. Let go of the gas pedal, and it stops- and drives smoothly. It’ll also do it on cruise control under the same conditions.
When I take off from a stop, it feels just fine really. It’ll take off without a problem and speed up. I may have said “any speed” in my first post but it’s really only in highway speeds. I can’t really get it to happen much under 60mph. It’s quite noticeable though. After I did a full injector set replacement, I noticed the problem on my test drive. Went and got rotate and balance to make sure.
In my first post I included a pic monitoring fuel pressure. I’ll attach another one here, showing the freeze frame values at the top when the issue repeated. I have a 6L80. Thank you

Interesting...If you only started noticing the issue after you replaced the injectors, i'd be inclined to think one or more of the injectors are defective in some way that isn't showing up in the data or something got missed or damaged during the repair.

This also sounds like worn ring/pinion, specifically when the drive side of your ring and pinion gear set is excessively worn...My trans am was making a very high frequency vibration at high speeds, off throttle so the coast side of the ring/pinion were worn...But you would have noticed this long before you changed your injectors. Plus those rear axles/diffs rarely go bad in daily driver vehicles with only 150ish on the clock...It's worth checking for bad wheel bearings, u joints, etc as well, if you havent already.

Only other potential cause I can think of atm is either front or rear gear set in the trans is going out...They typically dont thow any codes; diagnosis is done by analyzing symptoms on test drive then looking for gear chunks, pieces in the pan.

All of the above assumes the the tire rotation and balance was done correctly and that there's no wheel or axle bearing or shaft problems

 

[Doubeleive]

Absolutely. It is very consistent. Any time I’m going about 70mph and press the gas pedal a bit harder, it will recreate the problem almost every time. Let go of the gas pedal, and it stops- and drives smoothly. It’ll also do it on cruise control under the same conditions.
When I take off from a stop, it feels just fine really. It’ll take off without a problem and speed up. I may have said “any speed” in my first post but it’s really only in highway speeds. I can’t really get it to happen much under 60mph. It’s quite noticeable though. After I did a full injector set replacement, I noticed the problem on my test drive. Went and got rotate and balance to make sure.
In my first post I included a pic monitoring fuel pressure. I’ll attach another one here, showing the freeze frame values at the top when the issue repeated. I have a 6L80. Thank you

post up what the MAF is showing when the problem occurs, fuel pressure appears to be within spec (at least what is being commanded anyway)

 

[Td_symmons]

Interesting...If you only started noticing the issue after you replaced the injectors, i'd be inclined to think one or more of the injectors are defective in some way that isn't showing up in the data or something got missed or damaged during the repair.

This also sounds like worn ring/pinion, specifically when the drive side of your ring and pinion gear set is excessively worn...My trans am was making a very high frequency vibration at high speeds, off throttle so the coast side of the ring/pinion were worn...But you would have noticed this long before you changed your injectors. Plus those rear axles/diffs rarely go bad in daily driver vehicles with only 150ish on the clock...It's worth checking for bad wheel bearings, u joints, etc as well, if you havent already.

Only other potential cause I can think of atm is either front or rear gear set in the trans is going out...They typically dont thow any codes; diagnosis is done by analyzing symptoms on test drive then looking for gear chunks, pieces in the pan.

All of the above assumes the the tire rotation and balance was done correctly and that there's no wheel or axle bearing or shaft problems

Great info. Thank you. I’ll check many of that this weekend.

 

[Td_symmons]

post up what the MAF is showing when the problem occurs, fuel pressure appears to be within spec (at least what is being commanded anyway)

Sure thing. Will do. I was under the impression that I was monitoring the fuel lift pump pressure output from a (low pressure/lift pump) fuel pressure sensor. Is this not the case and it’s actually just the commander pressure ? Do I need to connect up a fuel pressure gauge?

 

[Doubeleive]

Sure thing. Will do. I was under the impression that I was monitoring the fuel lift pump pressure output from a (low pressure/lift pump) fuel pressure sensor. Is this not the case and it’s actually just the commander pressure ? Do I need to connect up a fuel pressure gauge?

a physical gauge is best to rule it out for sure, just stick it up under the hood so you can see it through the window
and may as well do a fuel pressure drop test at the same time since you replaced the injectors

 

[jyi786]

I'm having a very very similar issue in my 2019 Escalade ESV, so I'll be watching this thread. I know we have very different transmissions, but the symptoms are SPOT ON almost exactly the same.

On a side note, @Td_symmons what bi-directional scan tool did you use to get those graph screenshots?

 

[Td_symmons]

a physical gauge is best to rule it out for sure, just stick it up under the hood so you can see it through the window
and may as well do a fuel pressure drop test at the same time since you replaced the injectors

Great. Will do. Thanks!

@jyi786 great, hopefully we can get this sorted out together. I use my Autel mk808. I switched from autoenginuity in 2022. I really don’t like the Autel, but it’s one of the most cost efficient modern scan tools that had the functions I was looking for (had to include GM injection pressure drop testing).

 

[JrKinger]

So just had the same issue thought it was the the torque converter again. Took it to my mechanic who is great and he said all he could feel was the afm kicking in and out causing the shuddering and hesitation. So he deleted the afm and so far seems to have went away. It’s only been a week though so still need to see on a longer trip this week.

 

[Td_symmons]

So just had the same issue thought it was the the torque converter again. Took it to my mechanic who is great and he said all he could feel was the afm kicking in and out causing the shuddering and hesitation. So he deleted the afm and so far seems to have went away. It’s only been a week though so still need to see on a longer trip this week.

Great to know! I’ll see if I can do a test drive with AFM disabled

 

[trottida]

While I'm not familiar with the 2017 AFM, on the 2011's there is a screen in the driver center which shows you real time fuel mileage, within that screen it will show you if you are in 8 cyl or 4 cyl mode. If the shutter occurs when you are in 4 Cyl mode then it's likely your AFM system causing the shutter feeling until you apply enough throttle to kick it into 8 cyl mode. You mentioned disabling AFM - is that an option in the 2017's? I had to buy a Range AFM/DFM Disabler to do that.

 

[Doubeleive]

While I'm not familiar with the 2017 AFM, on the 2011's there is a screen in the driver center which shows you real time fuel mileage, within that screen it will show you if you are in 8 cyl or 4 cyl mode. If the shutter occurs when you are in 4 Cyl mode then it's likely your AFM system causing the shutter feeling until you apply enough throttle to kick it into 8 cyl mode. You mentioned disabling AFM - is that an option in the 2017's? I had to buy a Range AFM/DFM Disabler to do that.

it is not a oem option to turn it off on any of these vehicles. requires a tune out or removal of the components, the range device works but only does 1 thing for a little bit more you can get a lot more features.

 

[trottida]

it is not a oem option to turn it off on any of these vehicles. requires a tune out or removal of the components, the range device works but only does 1 thing for a little bit more you can get a lot more features.

That's what I thought regarding AFM disable. In my case I don't drive our Suburban enough to care about the extra options from a tune out. It's just a weekend vehicle to get back to our cabin pulling a trailer and/or a third vehicle to use in a pinch. I just wanted to get rid of the annoyance of the shutter in 4 cyl mode. I hope the Range device doesn't have any long term negative affects though. Time will tell.

 

[Doubeleive]

That's what I thought regarding AFM disable. In my case I don't drive our Suburban enough to care about the extra options from a tune out. It's just a weekend vehicle to get back to our camp pulling a trailer and/or a third vehicle to use in a pinch. I just wanted to get rid of the annoyance of the shutter in 4 cyl mode. I hope the Range device doesn't have any long term negative affects though. Time will tell.

no the only things I have ever seen is a few random reports of battery drain or the product failing over a period of time
and it appears that if you require a state vehicle inspection that checks smog equipment then it should be removed a couple weeks prior to inspection so all the sensors can set properly
disabling the afm in general is a benefit no matter how. other than a tiny mpg hit which can be extremely negligible.

 

[jyi786]

In my case, I'm 99% sure the shuddering has nothing to do with AFM. The truck goes in and out of V4/V8 mode seamlessly.

 

[Td_symmons]

In my case, I'm 99% sure the shuddering has nothing to do with AFM. The truck goes in and out of V4/V8 mode seamlessly.

I did multiple test drives last night. On one of them I monitored and reviewed almost every parameter related to the the AFM. Cylinder deactivation was never engaged when I was having the issues. No faults occurred. Both the dash and the parameter agreed that it was in v8 during the shake. I have noticed that it occurs close to 90% engine load and above.

I haven’t yet connected my fuel pressure gauge to verify that the (low pressure) fuel pressure sensor is accurate. I verified in the service manual that the measured fuel pressure is the output of the fuel pressure sensor near the tank, after the pump. The commanded fuel pressure is a separate parameter labeled “desired fuel pressure”.

During another test drive, I got a p0300 with a flashing MIL. Freeze frame data showed no misfires(?) - a test drive watching misfire data showed just a few small misfires here and there. Report and screenshots of misfire data at time of shake are attached.