Surging at slow speed while braking

[JohnPW]

I’m having multiple issues with my 2016 Land Cruiser, at least one of which is my fault for listening to the Toyota dealer. I previously posted on the intermittent squealing noise I’m getting at the front of the engine: Intermittent engine noise- diagnostic help? - https://forum.ih8mud.com/threads/intermittent-engine-noise-diagnostic-help.1313783/#post-14984783
That is occurring maybe once a week, when it does it it’s loud but most of the time it’s nonexistent. I took the truck to my local dealer for maintenance and to diagnose the problem, and that’s when my second issue started. They couldn’t replicate the noise, removed the serpentine belt and found nothing wrong….so that problem is still unresolved.

After getting the truck back from the dealer, I now also have an intermittent surging at very slow speeds while braking, in either D or Reverse. Very alarming feeling, the first time it happened I thought someone had hit me from behind…I’m almost stopped, or completely stopped, and the vehicle tries to surge forward (or backwards when in Reverse).

At the dealer visit I had them do oil change, air filter, tire rotation….and they convinced me to do a transmission flush, brake fluid flush, and some kind of induction system cleaning. Not sure how I was suckered in to fixing what isn’t broken, but I guess they caught me on an off day.

Now it’s back at the dealer but of course they can’t replicate as the problem is very intermittent. Any ideas on what the latest problem might be? I’m guessing the induction cleaning messed up vacuum systems? At first I thought it might be a transmission downshift but it happens in Reverse so probably not? Any advice appreciated.

 

[jivewalker]

I have one troubleshooting suggestion. I would check the two slip yokes in your drive shaft(s) for too much or not enough grease as quick start, especially if have been over greased and become "hydro-locked".

 

[paulunm]

That, and also- is your AC compressor cycling on and off when you notice the surging? That can cause a bit of a surge due to load and release of load from the compressor.

 

[JohnPW]

That, and also- is your AC compressor cycling on and off when you notice the surging? That can cause a bit of a surge due to load and release of load from the compressor.

No, the surge is MUCH bigger than what that might cause. It literally feels like someone just ran into the back of the vehicle.

 

[pigmony]

I sometimes have this problem in my work truck. It only happens when I'm wearing mud boots. The problem is that my boot is catching the edge of the gas pedal and I can't feel it through the thicker boot sole. It's only ever been an issue in my work truck. It must be a pedal spacing thing.

 

[JohnPW]

I sometimes have this problem in my work truck. It only happens when I'm wearing mud boots. The problem is that my boot is catching the edge of the gas pedal and I can't feel it through the thicker boot sole. It's only ever been an issue in my work truck. It must be a pedal spacing thing.

Appreciate all suggestions and thoughts. But that is not what is happening here. I have driven the LC for 5 years and never had anything like this until the day I picked it up from service. Assuming it must have resulted from their service, which was induction cleaning, brake fluid flushing, transmission flush. I’m thinking it might be some type of vacuum issue from what I’m reading online?

 

[lx200inAR]

Appreciate all suggestions and thoughts. But that is not what is happening here. I have driven the LC for 5 years and never had anything like this until the day I picked it up from service. Assuming it must have resulted from their service, which was induction cleaning, brake fluid flushing, transmission flush. I’m thinking it might be some type of vacuum issue from what I’m reading online?

I know this is going to sound like piling on, but any chance your floor mat isn’t seated properly? Toyota certainly had a whole thing with floor mats and surging.

 

[TeCKis300]

That is strange behavior indeed. Hard to guess what it could be.

I'll take a guess that maybe since they did the air filter, they didn't seat the cover or intake pipe to the throttle body correctly and the MAF is not metering air correctly on occasion and surging. Check for other vacuum leaks too.

 

[Sandroad]

All those type services are done in the dealers Express Lane bays by minimally trained employees who may or may not have done them well. The induction service and air cleaner replacement are suspect. Something may not be seated/sealed right or a plug was left open. The induction service can cause misfires and check engine lights. It’s also possible the transmission is low/high on fluid. I hope the service dept can eventually duplicate the surge or get a code. Otherwise they won’t do anything.

 

[NikP]

Transmission flush sounds like it changed the slip characteristics internal to the transmission. Id run it a while to see if things improve. What was the mileage and had trans fluid ever been changed? Also have the fluid level checked because its level is set at a very specific temperature.

 

[JohnPW]

Update, the dealer replicated the problem once while in reverse parking the truck, but couldn’t replicate while on the computer. They lubricated U joints on drive shaft and did a hard reset on the ECU. All fluid levels including transmission were good. I picked up the truck today and no issues on the return trip, it is driving well so far, fingers crossed although I remain skeptical that it is resolved. Resetting the ECU seems to have smoothed out shifts, which weren’t a problem before but the truck is driving well so far.

Still can’t consistently replicate the infrequent squealing from the front of the engine (the original problem in the link above) but hopeful that the second issue is resolved.

Lc200 is a 2016 with only 73k miles, my spending money on transmission flush and induction (both likely unnecessary) was a mistake, shame on me.

 

[TeCKis300]

The squealing is likely the accessory belt tensioner. Surprised they didn't recommend that. Perhaps a bit early for a 2016 of that mileage, but a common first thing to address to eliminate that possibility.

They probably found some dumb vacuum system mistake and are not owning up to it.

 

[jivewalker]

I'm still thinking slip yokes and spiders were over/under lubed. Was a popular issue on the 4Runner, including mine. Keep the driveline lubed properly, doubt the dealer does. When I took over maintenance on my 4Runner after free dealer maint and went to lube mine, there was still black factory paint on the zerks. If you pump too much grease in the slips they can't move properly and you have to remove the zerk to let it push back out.

 

[bloc]

They probably found some dumb vacuum system mistake and are not owning up to it.

Agreed.

 

[daneo]

Update, the dealer replicated the problem once while in reverse parking the truck, but couldn’t replicate while on the computer. They lubricated U joints on drive shaft and did a hard reset on the ECU. All fluid levels including transmission were good. I picked up the truck today and no issues on the return trip, it is driving well so far, fingers crossed although I remain skeptical that it is resolved. Resetting the ECU seems to have smoothed out shifts, which weren’t a problem before but the truck is driving well so far.


Lc200 is a 2016 with only 73k miles, my spending money on transmission flush and induction (both likely unnecessary) was a mistake, shame on me.

Question on the “surging” sensation. Does it feel like a downshift, just as you’re coming to a stop at ~3MPH? Causes the front end to dip? Sometimes with a noticeable “plonk” you can feel in the chassis.

If yes, I’ve been fighting this feeling in D since early on in ownership. TCU resets get rid of it temporarily. I also have the poor shift quality while doing rolling stops that also goes away with TCU reset. Would love if these were linked to a vacuum leak. Both my local Toyota dealership and the local Lexus dealership say these are “characteristics of the vehicle”.

 

[LvCruiserNewb]

Question on the “surging” sensation. Does it feel like a downshift, just as you’re coming to a stop at ~3MPH? Causes the front end to dip? Sometimes with a noticeable “plonk” you can feel in the chassis.

If yes, I’ve been fighting this feeling in D since early on in ownership. TCU resets get rid of it temporarily. I also have the poor shift quality while doing rolling stops that also goes away with TCU reset. Would love if these were linked to a vacuum leak. Both my local Toyota dealership and the local Lexus dealership say these are “characteristics of the vehicle”.

I have the same sensation in those conditions and dealers say its normal. Every once in a while the plonk is loud enough to scare the crap out of me that something is broken. Feels like something fell off the bottom of the truck. I sure as heck hope it's normal and not an early sign of impending failure.

 

[JohnPW]

Question on the “surging” sensation. Does it feel like a downshift, just as you’re coming to a stop at ~3MPH? Causes the front end to dip? Sometimes with a noticeable “plonk” you can feel in the chassis.

If yes, I’ve been fighting this feeling in D since early on in ownership. TCU resets get rid of it temporarily. I also have the poor shift quality while doing rolling stops that also goes away with TCU reset. Would love if these were linked to a vacuum leak. Both my local Toyota dealership and the local Lexus dealership say these are “characteristics of the vehicle”.

I believe what I was experiencing was different. First time it happened I literally thought someone had run into me from behind. But the problem happened as often in reverse as it did in Drive, so I have assumed it was not transmission related. My problem did feel like a “plonk” with a strong surge forward (or backwards when in reverse).

I have had odd shifts on occasion between 1and 2 in the past, especially if the vehicle hadn’t warmed up yet. But the problem I was experiencing was much worse and more abrupt than that…no way someone would think it’s normal.

The truck drove great yesterday, hopefully the problem is fixed. After the reset it is shifting better than it ever has for me, I hope shifting doesn’t get worse like your experience with multiple resets has been.

 

[JohnPW]

I have the same sensation in those conditions and dealers say it’s normal. Every once in a while the plonk is loud enough to scare the crap out of me that something is broken. Feels like something fell off the bottom of the truck. I sure as heck hope it's normal and not an early sign of impending failure.

I can’t imagine that being “normal”. I would try a different dealership or shop.