Jump to content

Highway Surging/Pulsing

EFLine

By EFLine
in Troubleshooting & Recalls

 Share

Recommended Posts

EFLine Enthusiast

EFLine

Posted
Posted

So I know we all have the shakes when it comes to our trucks, but I have been experiencing a new "feature".

 

I'll be driving down the highway around between 65-80mph depending on highway and traffic and get a surging or pulsing feeling. It almost feels like the transmission is slipping, or it's knocking itself in and out of overdrive. The RPMs do not jump and it's not when it shifts from V4 to V8.

 

Does not seem to matter if cruise is set or not, and will happen multiple times, sometimes consistently every 45 seconds (rough numbers). Just trying to say it's not a one time deal while I'm driving.

 

Any ideas?

BigBadSierra Senior Enthusiast

BigBadSierra

Posted
Posted

The first thing I would do is disconnect the battery let it sit for 10 minutes and then drive it again for a week and see if it comes back.

 

The last 6 GM's I have had ran on this LANBUS system and they all need a disconnect ever once and a while to start behaving again.

 

IF it comes back then you most likely are having an issue.

EFLine Enthusiast

EFLine

Posted
  • Author
Posted

Thanks BBS. funny you mentioned that. I had to do that last week because MyLink crapped out on me and disconnecting the battery, (along with the fuse) was a supposed "reset" for it. Might not hurt to attempt it again though to see what happens.

rcl New Member

rcl

Posted
Posted

Each time I had this problem I discovered a spark plug wire disconnected. First was the No. 1 cyl. Second was the No. 5. Not sure why they keep coming off the plug. Anyone else have this issue?

  • Like 1
EFLine Enthusiast

EFLine

Posted
  • Author
Posted

Each time I had this problem I discovered a spark plug wire disconnected. First was the No. 1 cyl. Second was the No. 5. Not sure why they keep coming off the plug. Anyone else have this issue?

Interesting, i'll go to the garage and check that out. You would think that this would throw a code, did you happen to notice if yours had a code or not for like a cylinder misfire?

15_silverado Enthusiast

15_silverado

Posted
Posted

EFLine what year, engine and trans do you have?

 

The spark plug wire problem is common; I think there was a hole thread on that, and maybe even a TSB....I see if I can find it. There's a metal clip inside the boot of the spark plug wire where it connects to the spark plug, that metal clip becomes loose or even falls out, then the spark plug wire will not stay on the spark plug. If you have this problem you are supposed to replace the spark plug wire.

 

The surging is a separate problem I believe, especially depending on what year your truck is. There's been other posts/complaints about this. Apparently for the 2016-17 GM knows about this and is working on a reprogramming solution. The engineers said the trans needs more slip to be smooth but the trans engineer says more slip may cause damage to the transmission. (This info comes from another member who works at a dealer, I'll see if I can find that tread)

rcl New Member

rcl

Posted
Posted

No codes. The engine light went on and off intermittently which might be related to the clip on the spark plug wire bouncing on and off of the plug. When I got home I plugged my code tester in and it gave me a 0305 code, (don't quote me on the code number, going from memory last night), and stated "cylinder 5 misfiring". It's easy to find just give the wire a little tug and you'll see it's just disconnected. I stopped at the GMC service dept today, told them about my two incidents and they said they had not heard of any issues with this. If you find that thread or TSB Bob I'd be interested in seeing that. Thx

15_silverado Enthusiast

15_silverado

Posted
Posted (edited)

No codes. The engine light went on and off intermittently which might be related to the clip on the spark plug wire bouncing on and off of the plug. When I got home I plugged my code tester in and it gave me a 0305 code, (don't quote me on the code number, going from memory last night), and stated "cylinder 5 misfiring". It's easy to find just give the wire a little tug and you'll see it's just disconnected. I stopped at the GMC service dept today, told them about my two incidents and they said they had not heard of any issues with this. If you find that thread or TSB Bob I'd be interested in seeing that. Thx

Spark plug wires

 

http://www.gm-trucks.com/forums/topic/193036-loose-spark-plug-wire-heres-the-fix/

 

http://www.gm-trucks.com/forums/topic/175878-spark-plug-wires-coming-off/

Edited by 15_silverado
  • Like 1
EFLine Enthusiast

EFLine

Posted
  • Author
Posted

Hey guys, been out of the country and love all the great info and will read through this tonight. I really appreciate the links!

 

I will follow up with what I find.

 

Will have to investigate a tad more but it MIGHT be a pulsing or surging with V4 mode (AFM) that I didn't think was the case before... but coming back from the airport I watched it super close with the pulsing / surging and seemed to possibly correlate to when AFM kicked in. :dunno:

  • 4 years later...
whistleblower Enthusiast

whistleblower

Posted
Posted

Realize I'm bumping an old thread but I just purchased a used Yukon XL with the 6.2L and 62k miles and 10 speed transmission.  I noticed this 'pulsing' when driving it 7 hours back home on the highway 70-80mph.  This is my first time driving the 6.2L.  Did you ever find a fix for your issue?  Is this a common problem?  As the OP mentioned, feels like the transmission is slipping...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,947
    Total Members
    8,960
    Most Online
    Sothpaw27
    Newest Member
    Sothpaw27
    Joined

  • Who's Online   1 Member, 0 Anonymous, 443 Guests (See full list)

  • Latest Articles

  • Posts

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      www.enginelabs.com/news/what-i-learned-today-bearing-clearances-vs-oil-viscosities/     www.enginelabs.com/news/oil-viscosity-can-the-numbers-be-misleading/ The Big Lie… Coming full circle to the reason Lake discusses the Porsche engines in particular. Based on the 2000 samples in the SPEEDiagnostix database, increasing the oil viscosity in these engines, even those run on the track, showed no significant difference in results.   The smoking gun was in the oil chemistry. That is where the data shows higher instances of more wear. Molybdenum was the key; the higher the amount, the less the wear. Speed postulates that higher viscosity oils have more thickeners to artificially inflate their viscosity numbers. These thickeners lose viscosity under shear, and the result is that not all oils of the same viscosity have the same shear stability.   Having enough viscosity is the most important characteristic, but according to Speed, once that required viscosity level is reached, additive chemistry matters more than additional viscosity. Speed also states, oil pressure problems on the racetrack aren’t a viscosity problem; it’s an oiling system problem. Running a thicker oil is just a band-aid for an underlying oiling system problem.
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled II?   Viscosity on the decline by various means. Heat on the rise making that worse. Engine RPM in the tank. Smaller motors with more boost trying to emulate an electric motor. Full torque, zero rpm. Then we will triple the OCI. Argh.    But wait....there is more. LSPI has pushed a shift from Ca to Mg and as that cost more PLUS the run to lower sulfur compounds the TBN is moving in the wrong direction for the increased OCI's demanded.    That not being enough to placate a demand for a parameter they can't measure the other sulfur bearing compounds are also under attack. That would be zinc and phosphorus sulfonate compounds. To some degree those are being replaced with boron esters and others, i.e. titanium ect. All of which have shorter service lives. And there there is the "Secrete Sauce" marketing for AW adds that 'Can't be detected by UOA's" but trust me because I (the blenders) never ever lie.    Spoiler alert; ALL additives are sacrificial! Smaller amounts of the old blended with less robust versions of the new do not equal longer service lives. So what are the blenders recommending? Wait for it.......   MOVING THE GOAL POSTS! OMG      Let's declare the long standing TAN/TBN crossover irrelevant and tell people that soot is a great 'graphite' based lubricant which can aid tribo films. Wait, what? Let's declare that the standards used for oxidation and nitration were to conservative and can be expanded. Let's tell them that because GDI fuel dilution, although being a VISCOSITY KILLER and an acid generator is actually okay because we have better base oils that limit viscosity failure limits. (Said knowing this is measured in fractions of a centipoise and in bases not commonly used in shelf oils)   Lying from the heart is not just the new normal but we have a public, a very young public, that is so ignorant of the facts and so sure of their "RESEARCH" into AI driven models base in regurgitated  instead of scientific research based unvarnished, peer reviewed FACTS that the incoming guard is loosing their grip on reality and the OEM's are tickled pink while the blends bend the knee.    You have an ever limited set of tools to work with. And sooner or later those will be taken from you as the API and the EPA strangle the last remaining fluids from the system. What you have left is your wits. If you care to use them.    At some point in the very near future it will not longer be possible to do "What is best for the machine", and be replaced with "The best you have access too". You WILL be rewarded with half the life and twice the cost. That isn't that hard to predict.         
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I trust you saw the other comment where he knew what he was talking about !. Yes, these darned newer vehicles with all their so smart they are stupid technology, goes and drains the battery down. As you might see my other comment, I installed a Noco 5 battery tender under the hood and at this point still have the cord routed so I have to lift the hood and then plug it in but am typically parked in a garage or a shed so its not risking the engine hood in the wind. That way I am assured or hopefully so of not finding I have a battery drawn down and can't even start the truck and that also damages the battery to draw it down too far. 
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I guess no surprise my guesses were wrong !, at least now I know if I ever happen to see it grayed out in my own truck as to what is going on.    I never happened to catch my truck with it grayed out, it seemed every time I would test to see if there was an update it never found anything and yet more than once I would check to see if there was an update and there was nothing, then a day later or even that same morning I would drive to town and after more than one engine shut down in town as I did my errands it would pop up that there is an update now ready to install and the only place I have a connection to the internet is at home by wifi so its not as if it grabbed the download while driving. I don't trust these new vehicles due to all the crap they can decide to do while sitting for some days not running and run the battery down so most of the time if I know the truck will sit for a few days I plug in the battery tender I have mounted under the hood and so the only time the truck must have downloaded software was when it was sitting in the garage where the signal is awful but I have that tender plugged in and somehow it managed to download it. I honestly detest all this crap, way to easy to leave a person stranded.    Since I don't trust any of it I don't do the install of the already downloaded software until I get home and sometimes have even sat in the truck to watch what its doing as its going through the process to its conclusion as its not like it is set up that it will tell you the next time you fire up the engine that the update that was initialed actually installed or installed properly. Yes I can go into the updates and see the list. After I go through the install where I feel its safe to do so in case it breaks down as a result, I will plug in the battery tender after the fact to recharge as I don't know how much power its taking just to do the install and that can take a while for it to install. 
    • nfisherman
      Software Update

      By nfisherman · Posted

      Thanks for the reply. All settings were correct and the engine was off, as it was supposed to be. It turned out to be something simple. I took a drive for about an hour. I must have had a low battery without knowing it. The voltage gauge on the display looked ok. At the end of my drive, I shut off the engine and the update prompt came up and it updated normally. It’s ironic because one of the features of the update is a reduction of battery drain. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...