Random loss of power from accelerating from a stop at low RPM

Cterry2 · December 27, 2021

To start out a little background: I am in a 2014 GMC Sierra 1500 5.3 149,000 miles. I have been daily driving this truck for two years now and have put 35,000 miles on it. This issue is completely out of the blue and I am hoping someone similar has fixed this issue in their truck. So I am having an issue that it seems a lot of us have had with our trucks on here however out of the multiple threads regarding the issue none are recent nor have a fix that I can find. Starting about 2 weeks ago I felt my truck do this weird surge/misfire/trannyslip feeling whenever I was going down the road I didn't think much about it until I was going up the mountain the next day and it got a lot worse (more frequent) real quick. Well here I am a couple weeks later and this is everything I know about it. This feeling is almost like the truck is choking for power for a split second and then fixes itself and goes on about its business. Mash of the gas fixes it, downshift usually fixes it. It only occurs between 1500-1900 RPM but never whenever cruising at those RPM's on the highway on cruise. If I am coming from a stop then it will get through first gear just fine but at the top of second and usually the top of third it will what I thought was the tranny slipping for the longest time but it is just like the truck will hit a wall of power loss and it will only last 1-3 seconds. It never happens if I give it good gas only whenever I am around 25-30% throttle. From the other threads it seemed like mass consensus was that it was the torque converter however I read of one fella on here that replaced his entire transmission after a plethora of sensor changes and it still persisted. The only thing I have ben able to collect from the threads before me is that a tune HELPS make it less noticeable but not a single person has been able to make it go away completely. And it seems there have been a ton of yall that have experienced the same issue. It is throwing no engine codes, I even try to make it last longer sometimes by backing off the gas when it occurs to see if it will throw a code so that it will point me in a direction. This is a feeling felt by everybody in the truck. Stabilatrak off/trailer mode/manual mode, nothing makes a difference on it. Any tips/knowledge/help at all would be greatly appreciated.

M1ck3y · December 27, 2021

I think what the other threads are referring to is when the trans tests itself for wear. It will compare the test to the baseline and make the necessary adjustments to maintain proper function, shift feel etc.

What your describing seems to be a consistent issue in specific gears. Or maybe... Because you screw around with it during the test, it gets wildly different results each time. Confusing the hell out of it :dunno:

16LT4 · December 27, 2021

I had an '04 F150 FX4 with the 5.4 3v that would shudder horribly in 3rd and 4th gear, especially with the TC locked, under light throttle; opening the throttle and downshifting also cured symptoms. Once, the shuddering was so bad the center console lid started to crack at the hinge. Finally, I was able to hammer it enough to throw a CEL for a misfire code, #3. At that point, I replaced all the coils, and soon thereafter all the spark plugs; at 140k miles, I managed to not break a single plug.

A couple of transmission drain/fills, with a 10oz bottle of lubegard red, solved the faint TC-locked "shudder" (I wouldn't even call it that... more like "fuzzy" for lack of a better descriptor).

So, that is a long-rambled way of saying 1) check for pending codes, particularly misfires and 2) if you have over 60k on your plugs and wires, go ahead and change them. Many manufacturers that sold vehicles with "100k mile plugs" have since backed off and lowered the replacement schedule to 60k miles. Plugs for a Chevy are only a few bucks, and take under an hour on, taking one's time to clean the wells and threads.

Edited December 27, 2021 by 16LT4

steelerdude15 · December 28, 2021

When was the last time you serviced your transmission?

Cterry2 · December 28, 2021

19 hours ago, M1ck3y said:

I think what the other threads are referring to is when the trans tests itself for wear. It will compare the test to the baseline and make the necessary adjustments to maintain proper function, shift feel etc.

What your describing seems to be a consistent issue in specific gears. Or maybe... Because you screw around with it during the test, it gets wildly different results each time. Confusing the hell out of it

I’ve never heard of this tranny test, I’d be interested to learn more about that. It’s possible I have been altering the results although I have only been dragging out the symptom here recently to try snd induce a CEL.

18 hours ago, 16LT4 said:

I had an '04 F150 FX4 with the 5.4 3v that would shudder horribly in 3rd and 4th gear, especially with the TC locked, under light throttle; opening the throttle and downshifting also cured symptoms. Once, the shuddering was so bad the center console lid started to crack at the hinge. Finally, I was able to hammer it enough to throw a CEL for a misfire code, #3. At that point, I replaced all the coils, and soon thereafter all the spark plugs; at 140k miles, I managed to not break a single plug.

A couple of transmission drain/fills, with a 10oz bottle of lubegard red, solved the faint TC-locked "shudder" (I wouldn't even call it that... more like "fuzzy" for lack of a better descriptor).

So, that is a long-rambled way of saying 1) check for pending codes, particularly misfires and 2) if you have over 60k on your plugs and wires, go ahead and change them. Many manufacturers that sold vehicles with "100k mile plugs" have since backed off and lowered the replacement schedule to 60k miles. Plugs for a Chevy are only a few bucks, and take under an hour on, taking one's time to clean the wells and threads.

Thanks for the replay. Do you think your issue was fixed more by the plugs or granny service?

14 hours ago, steelerdude15 said:

When was the last time you serviced your transmission?

Honestly I haven’t ever. That was next on the list as long as nobody was like “torque converter! Torque converter!” Then I’d have to refill with fluids anyways after replacing lol.

Cterry2 · December 28, 2021

On 12/27/2021 at 9:44 AM, Cterry2 said:

To start out a little background: I am in a 2014 GMC Sierra 1500 5.3 149,000 miles. I have been daily driving this truck for two years now and have put 35,000 miles on it. This issue is completely out of the blue and I am hoping someone similar has fixed this issue in their truck. So I am having an issue that it seems a lot of us have had with our trucks on here however out of the multiple threads regarding the issue none are recent nor have a fix that I can find. Starting about 2 weeks ago I felt my truck do this weird surge/misfire/trannyslip feeling whenever I was going down the road I didn't think much about it until I was going up the mountain the next day and it got a lot worse (more frequent) real quick. Well here I am a couple weeks later and this is everything I know about it. This feeling is almost like the truck is choking for power for a split second and then fixes itself and goes on about its business. Mash of the gas fixes it, downshift usually fixes it. It only occurs between 1500-1900 RPM but never whenever cruising at those RPM's on the highway on cruise. If I am coming from a stop then it will get through first gear just fine but at the top of second and usually the top of third it will what I thought was the tranny slipping for the longest time but it is just like the truck will hit a wall of power loss and it will only last 1-3 seconds. It never happens if I give it good gas only whenever I am around 25-30% throttle. From the other threads it seemed like mass consensus was that it was the torque converter however I read of one fella on here that replaced his entire transmission after a plethora of sensor changes and it still persisted. The only thing I have ben able to collect from the threads before me is that a tune HELPS make it less noticeable but not a single person has been able to make it go away completely. And it seems there have been a ton of yall that have experienced the same issue. It is throwing no engine codes, I even try to make it last longer sometimes by backing off the gas when it occurs to see if it will throw a code so that it will point me in a direction. This is a feeling felt by everybody in the truck. Stabilatrak off/trailer mode/manual mode, nothing makes a difference on it. Any tips/knowledge/help at all would be greatly appreciated.

I need to add a new symptom I am noticing. I have a tuner/gauge that shows my throttle percentage and whenever this hiccup happens my throttle with increase substantially from anywhere I am like 25-40% as soon as I feel it begin to hit that wall of no power I look down and the throttle is reading 75 to sometimes 99% without me moving the gas pedal at all. Unsure where the gauge gets this reading but thought I would put that out there. I wouldn’t think it was in the tuning as I haven’t messed with it, anything for that matter, and it just came out of the blue.

steelerdude15 · December 28, 2021

One more question for you. Does it act like this only when the truck is cold or at any time?

16LT4 · December 28, 2021

5 hours ago, Cterry2 said:

I’ve never heard of this tranny test, I’d be interested to learn more about that. It’s possible I have been altering the results although I have only been dragging out the symptom here recently to try snd induce a CEL.

Thanks for the replay. Do you think your issue was fixed more by the plugs or granny service?

Honestly I haven’t ever. That was next on the list as long as nobody was like “torque converter! Torque converter!” Then I’d have to refill with fluids anyways after replacing lol.

The bad coil 100% cured the misfire (which was the cause of the shuddering/shaking, sorry that wasn't clear); the new plugs made the engine run better.

If you're unsure of spark plug history, do them yesterday. They cost pennies, and at your mileage you should be on your third set. Transmission should be serviced every 15-45k miles, so again assume it's never been done. Fluid also costs pennies; plan to drop the pan and replace the filter. In the case of my Ford 4r75, a few drain/fills plus the Lubegard red on the last one made a very drastic difference with its shifting, eliminating the OD-TC-lockup vibration; at 142k miles, it had never been serviced.

Cterry2 · December 29, 2021

4 hours ago, steelerdude15 said:

One more question for you. Does it act like this only when the truck is cold or at any time?

No, I have been making sure to note this hoping to find some sort of correlation however it has done it cold or hot, first part of the drive or after driving for a bit.

1 hour ago, 16LT4 said:

The bad coil 100% cured the misfire (which was the cause of the shuddering/shaking, sorry that wasn't clear); the new plugs made the engine run better.

If you're unsure of spark plug history, do them yesterday. They cost pennies, and at your mileage you should be on your third set. Transmission should be serviced every 15-45k miles, so again assume it's never been done. Fluid also costs pennies; plan to drop the pan and replace the filter. In the case of my Ford 4r75, a few drain/fills plus the Lubegard red on the last one made a very drastic difference with its shifting, eliminating the OD-TC-lockup vibration; at 142k miles, it had never been serviced.

See I was wondering if this wasn’t a misfire however I have thrown not a single code so far through all of this. If it doesn’t go away as randomly as it came on I’ll probably go the route of tranny flush first then plugs.

steelerdude15 · December 29, 2021

1 hour ago, Cterry2 said:

No, I have been making sure to note this hoping to find some sort of correlation however it has done it cold or hot, first part of the drive or after driving for a bit.

See I was wondering if this wasn’t a misfire however I have thrown not a single code so far through all of this. If it doesn’t go away as randomly as it came on I’ll probably go the route of tranny flush first then plugs.

With our trucks, an issue can develop where it feels like the truck is chugging or “fish biting.” A transmission fluid and filter change can help take care of the issue. There is a TSB on the issue.

16LT4 · December 29, 2021

22 hours ago, Cterry2 said:

No, I have been making sure to note this hoping to find some sort of correlation however it has done it cold or hot, first part of the drive or after driving for a bit.

See I was wondering if this wasn’t a misfire however I have thrown not a single code so far through all of this. If it doesn’t go away as randomly as it came on I’ll probably go the route of tranny flush first then plugs.

No vehicle will illuminate a CEL for a single, or even multiple, misfires. The threshold can be quite high, as in the case of my F150 shaking the center console lid above. A quality scantool will show pending codes as well as misfire counts per cylinder, which would offer you more insight. If the history is unknown, you have to assume nothing has been done to the truck. This includes new plugs, wires, fluids and filters. Mechanical issues don't usually tend to repair themselves.

On the final drain/fill, I can't recommend a bottle of Lubegard red enough. If the trans can be smoothed out with new fluid, this will do it. My 135k mile 2004-r has survived a hard life behind 4 different engines, including a 455 and now a 350, and LG has been a part of it for years, so there's some anecdotal positives.

Edited December 29, 2021 by 16LT4