Engine jumping out of the car when letting go of the gas pedal? Wtf?

Joined
Aug 24, 2005
Messages
19
Location
Kahlifonia
Ok my father, the eternal perfectionist is persuaded that his '00 LX470 is bunk. He claims that at 70mph, letting go quickly of the gas pedal and then pressing back down on it, he feels like the engine is gonna go forward and jump out of the car.

I told him he's going nuts.

I had the engines mounts and the tranny mount changed.

Same problem.

I honestly dont feel anything and I think it's normal.

He listens to old @&@&@&@&s that come to his shop and they tell him crap like fuel sensors need to be replaced b/c it cuts off the fuel when he lets go of the gas pedal etc. What the hell?!?

Someone please shed some light on this "problem." He wants to sell it thinking there's something wrong w/ it.

Just like when he thuoght that the tranny was dying because when it went fromt R, backed the car, and then back to D, it would make a tiny itty bitty clunking sound. I told him, to sit for 2 minutes before taking off in the morning, and oh guess what, it doesnt do it then. Sheesh.

So tell me, if this is REALLY a problem, what do you think it could be? This is driving me nuts. He wants to sell it at a loss. Only had the thing for 6 months. He comes from a '00 E320 Mercedes. Never owned an SUV. I guess he expected too much refinement from this thing.

thanks.
 
Joined
Jul 7, 2004
Messages
1,516
Location
EVERGREEN, CO, USA
Chances are there is no major problem. He is not a LandCruiser person; it takes a while to get use to the idiosyncrasies of a LC.

LandCruisers are not a MercedesBenz; they are two different animals. There are numerous forums that discuss your "problem" and they all turn out to be user preference. Most of the LC nuts on this and other dedicated groups learn to live with the noises and stuff; in fact, if we don't hear them we think something is amiss.

...
 
Joined
Jun 20, 2005
Messages
265
Location
southern california
I would simply explain to him an even throttle would be easier on the engine, trans etc. ... and doesn't really need to release and stomp on the throttle, for what reason?

Buy him a three day session at Jim Russell for Christmas...

Jim Russell Racing
 
Joined
Aug 24, 2005
Messages
19
Location
Kahlifonia
He says that he does that when he's behind someone who suddenly taps the brakes and the lights come on, so he takes the foot off, and then sees that the car isnt slowing down, so he puts the foot back on the gas pedal. I guess normal driving. It's not what I question, rather it's his expectation from the LExus.

Do you guys feel anything like that?
 
Joined
Jun 20, 2005
Messages
265
Location
southern california
The Godfather said:
Ok my father, the eternal perfectionist is persuaded that his '00 LX470 is bunk. He claims that at 70mph, letting go quickly of the gas pedal and then pressing back down on it, he feels like the engine is gonna go forward and jump out of the car.

So tell me, if this is REALLY a problem, what do you think it could be? This is driving me nuts. He wants to sell it at a loss. Only had the thing for 6 months. He comes from a '00 E320 Mercedes. Never owned an SUV. I guess he expected too much refinement from this thing.

thanks.
Is that a typo or did he buy a five-to-six year old LX ? ...

and yes, I also expected refinement from my new LC, but I'm coming out of a Jeep so I guess you can say I'm stepping up in the world. Some people can't make that transition to a taller-wider vehicle. Have you considered he just doesn't like driving a mid-to-full size SUV ?

Back to his concern... new or used, the description of the problem is very nebulous. At any speed my LC engine doesn't act like it wants to jump out of the car ... it only has 235 hp.

Now if you were to ask the same question about throttling my Hemi car, then I guess you could say it feels like an Elephant wanting to "jump out of the car".
 
Joined
Aug 24, 2005
Messages
19
Location
Kahlifonia
Yeah my dad exaggerates sometimes. I've driven it plenty of times and never felt like something was that messed up. And yes, it IS a 2000.

Perhaps he just doesnt like an SUV. I dont know.

You guys dont have any other suggestions of what could probably be giving the car a slight abnormal jerk when letting go of the gas and then back on it?
 
Joined
Apr 10, 2003
Messages
1,186
Location
Kansas City, MO
 
 
 
Well, at 70 MPH, the vehicle is running at... let's say 3000 RPM. (not sure, just using for example).

Since it's an automatic, if he lets up off of the gas, the engine RPM's can slow down more than with a manual in relation to the speed of the vehicle, say... 2,000 RPM, whereas the drivetrain is still going at around what would be 2900 RPM.

When he hits the gas again, the torque converter connects with the transmission, causing the engine to speed back up to 2900 RPMs with the aid of drivetrain momentum.

This is normal for any automatic vehicle.

Are you close enough to him that you can drive it or at least ride in it and make sure this isn't a problem above and beyond what I just described?

EDIT:

And another thought, in many auto transmissions (not sure of the Toyota/Lexus one), letting off the gas and hitting it again drops the transmission a gear, into a "passing" gear. Could be that too.
 

hoser

SILVER Star
Joined
Dec 21, 2003
Messages
10,284
Location
Bay Area, CA
 
 
 
The Godfather said:
He says that he does that when he's behind someone who suddenly taps the brakes and the lights come on, so he takes the foot off, and then sees that the car isnt slowing down, so he puts the foot back on the gas pedal. I guess normal driving. It's not what I question, rather it's his expectation from the LExus.

Do you guys feel anything like that?
Do some searching in the 80's section specifically the 95-97 model years as the transmission is the same as the pre '03 100's. I would look more closely at the torque converter or transmission components. Here is one thread that talks about similiar symtoms except he gets it between 1-2 gear.

https://forum.ih8mud.com/showthread.php?t=35560&
 
Last edited:

NorCalDoug

problems solved daily...
Joined
Oct 27, 2003
Messages
6,217
Location
uhhhh...duh...Northern CA
 
 
 
The Godfather said:
Yeah I know that this isnt really the forum for that lol. Other than clublexus, do you have any other recommendations?
there's the lexusownersclub.com

...if you want good tech info, I wouldn't bother with LOC or CL. This is where you want to be. I saw your post on CL the other day and was going to suggest that you check here...but got distracted...
 
Joined
Aug 24, 2005
Messages
19
Location
Kahlifonia
Ok UPDATE: I drove the car yesterday for 500 miles. I can feel the problem he's talking about. In normal driving, you let go of the gas pedal to slow down and then apply gas normally and you feel that thud. I stopped by Lexus to make the service guy check it out and he heard it. Thought it was a bit weird. Then we drove another similar in miles and year LX470 and it did the same. So we thought ok, must be normal.

HOWEVER. AFter 160 miles, I got off the freeway and stopped. When I was stopped for 10 seconds, I felt a loud thunk coming from the rear (where all the sound is actually coming from). I thought I got rear ended but nobody was there. IT was the tranny doing a funky thing.

Im catching up on reading on that 80 series thread.

TB cable ?
 

FinallyGotOne!

SILVER Star
Joined
Jan 5, 2005
Messages
336
Location
Huntsville, Alabama
 
 
 
I have what I would call "driveline lash" from my Chevy days in my 2000 LX 470. Sounds a whole lot like what you are describing here, but certainly not as bad. I wouldn't even come close to describing it as the engine jumping out.

When I took it in to the dealer, they returned it and said -- and I mean to quote -- "That is to be expected in big and clunky SUVs"

I about fell over when I heard that! In my Blazer I would have been looking to replace the U joints. I'll just let this play out and see if it gets worse. I've got another 40K miles on my warranty.
 
Joined
Jan 4, 2005
Messages
57
Location
Alabama
Big heavy awd vehicle, combined with agressive stop and go driving is always going to equal two things...... the clunk and accelerated brake pad and rotor wear.

Symptoms sound normal for loading and unloading of the drivetrain, but it wouldn't hurt to have the components inspected and lubed. Maybe the green grease can lessen the severity of the clunk.
 
Joined
Aug 24, 2005
Messages
19
Location
Kahlifonia
You're correct about the lash thing and loading and unloading the drivetrain. The only thing that is weird is why it would do it at a stop. Could the differential mount need to be replaced?
 

hoser

SILVER Star
Joined
Dec 21, 2003
Messages
10,284
Location
Bay Area, CA
 
 
 
There is tension in the drivetrain when you're stopped and on the brakes. As soon as you release the brakes, just slightly, it can clunk. It will usually happen at stoplights. When the light turns green and you get ready to go... clunk. Is that what you mean by "do it at a stop?" Lube and check everything as per the link I posted earlier and let us know how things go.
 
Joined
Jun 20, 2005
Messages
265
Location
southern california
A slip yoke eliminator (SYE) cured this problem on my XJ. I haven't crawled underneath my LC yet to see the engineering marvel... I wonder if there's a similar SYE available for the LC/LX?
 
Joined
Aug 24, 2005
Messages
19
Location
Kahlifonia
hoser said:
There is tension in the drivetrain when you're stopped and on the brakes. As soon as you release the brakes, just slightly, it can clunk. It will usually happen at stoplights. When the light turns green and you get ready to go... clunk. Is that what you mean by "do it at a stop?" Lube and check everything as per the link I posted earlier and let us know how things go.
I'll do the things from the link you gave me. Thanks!!!!


a990dna, what does that do? Does it change the stock characteristics of the vehicle in such ways that comfort is better, or worse or what? Im not technical at all, so I don't know what it does. Thanks.
 
Joined
Jun 20, 2005
Messages
265
Location
southern california
The Godfather said:
I'll do the things from the link you gave me. Thanks!!!!


a990dna, what does that do? Does it change the stock characteristics of the vehicle in such ways that comfort is better, or worse or what? Im not technical at all, so I don't know what it does. Thanks.
No, a SYE eliminates the weak point and slip-yoke in the output shaft section of a transfer case... I checked underneath and the LC was engineered with a more robust fixed-yoke and driveshaft design, I'm impressed.

Forget I said anything, I'm sure the cure herein will do the job.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top Bottom