2006 Lx470 Throttle Pulse at 2200 rpm

[Thewjsand]

Hi all, this is my first real post. I searched hi and low and have not found this issue described as i have have it.

I own a 2006 LX470 that i purchased from Virgina and drove back to Minnesota. About 2 hours on the road i noticed very subtle pulse while cruising with the control on. I was going up a slight incline and the it was as if the cruise control could not decide if it wanted to give it more throttle. Pulse is about a second long and repeats 3 or 4 time then it either increases the throttle or it doesn't. After this I got closer to the mountains and it started to do it almost predictably. In the mountains it was horrible. I tried down shifting into 4 and it would still do it. I would have to give it gas to push past this zone of hesitation. I have pretty much narrowed it down the following:

2100-2400 Rpm
Occurs with: Cruise control, constant throttle (pedal control), and brisk acceleration
I can repeatedly introduce if i accelerate hard on decent incline
Will do it in 5th and 4th gear (easier to induce in 5th)
It is not mechanical or has no mechanical sounds or feels
Not the APPS.
No codes or lights

Note1:This truck has seen every single recommended maintenance from a Lexus dealer since new (has 126,XXX on it, just had the full 120K service).
Note2: There is a gas tank gauge issue as well on this car...if it sits for 24 hours it reads empty.

I brought it to my toyota dealer (they have done all the work on my 4x 4runners). They captured this on a monitor (see attached).
They felt that it was throttle body related and recommended that i take it to Lexus because they have a better Customer care warranty than Toyota which has a 8 yr 150K mile warrant on throttle body while Lexus has a 10 yr.

I took it to Lexus and they had a hard time inducing the issue, but after about 3 days the lead technician found it. He is having a hard time pin pointing the issue but reluctantly thinks it maybe the throttle body. They contracted Lexus engineering and described the issue. They said that if there was an issue it would through a code. There is no codes. They captured the waves just like toyota did. They are dumb founded, they claim that they have never seen or heard of anything like this.

Now i am in a bit of a situation: Lexus says that if it is the throttle body they will cover everything, if they replace the throttle body and it doesn't fix it then I will have to pay for the parts and labor.

What would you do?

I called Cruiser Creations in NH and described the issue. I believe his name was Dave and he told me he drove this problem on a 07 and that "the throttle body is junk". Coming from a cruiser specialist this is a confidence builder.

I did talk to Lexus a little more and made my case and it seems the dealership is willing to take a little more accountability that originally communicated. They are going to put a new throttle body in next week and test it out. They, understandably, don't want to be stuck with the part+labor if it doesn't work but it sounds like they might be able to return it to Lexus, s they agreed to try it.

Has anyone had this issue? is there a post like this that i missed during my many searches??? And what would you do?

Thanks! Matt

 

[elk]

It sounds like a possible TPS/APPS issue from what I've read. I have a similar issue, manifested as hesitation between 45-50 MPH going uphill. I've been chasing it, but the problem is intermittent at present.

https://forum.ih8mud.com/threads/tps-apps-problems.127474/

 

[RND1]

Sounds like you're on the right path. Let us know if the new TB fixes it?

 

[Thewjsand]

For me it has occurred at a large range of speeds, at cruise in mountains it was at 60-75, when accelerating it can happen at much lower speeds. Since it also happens in cruise (pedal in full extend position) i doubt it is the APPS. Try inducing it with either a steep grade or towing or loading the car with people. For me those almost guarantee it will happen. It was hard to induce in MN where i live the grade is very flat near the lakes where i live.

Also note, the previous owner noted this issue and her Lexus dealer said "Its and old car don't worry about it". which is total BS in my opinion.

I will give an update later this week after the TB is swapped out.

Thanks.

 

[Thewjsand]

Also the dealer stated that the TB is electronically control on 06-07 which is different than all other model years so if this issue is the TB it will be isolated to those years. Also potentially indicating that the typically discussed issues on this site for 99-00 does or may not apply in this case.

 

[elk]

Understood, there is discussion in the thread about the '03+ TPS concerns. It sounds as if your dealer will be supportive in the matter, so if you can readily reproduce the problematic scenario after the repair, it doesn't sound as if you stand to lose much. You mentioned that the dealer would try to return the part if unnecessary.

 

[Thewjsand]

Bummer news: The throttle body did not fix the issue. Lexus put a new part in and test drove it; still pulses/hesitates during acceleration. I also drove it and confirmed that during acceleration it still pulses or hesitates. Major bummer cost me 305$ to find that out.

Back to the drawing board.

The lead Tech said that he measured the cylinder banks and the engine is running very lean (nearly out of spec i think he near 2.5 ? (unsure of units))...I will do some searching but if anyone has any ideas I would appreciate it.

For now i am going to try running 93 Octane gas, maybe some fuel injector cleaner through this weekend and play the waiting game. If it would throw a code that at least would help narrow the search. I just don't have the cash to pay the dealer to chase the problem.

 

[Thewjsand]

Update: I solved the problem, thanks to a post on a FJ cruiser forum.

I found this forum on line and the post described my issue exactly:
http://www.fjcruiserforums.com/forums/problems-dealer-service/104575-annoying-surge-2-3k-rpm.html

A new fuel pump was about 380$ and Lexus was quoteing me $800. Local Toyota dealer quoted me $700.

In addition this truck had issue with the fuel guage (it would drop to empty if it sat for long time). Which in our truck is part of the Fuel Pump Assembly. I also want to note that Lexus quoted me 6 hours of labor to fix the gas gauge. (!? the assembly was accessible through a panel on the interior under the driver side rear seat.)

In talking to the service manage at the toyota dealer, he said that after market pumps have poor reliability even the Denso ones are not built to the same factory spec limts. But he suggested i source a complete fuel assembly from parts source they use for OEM parts. I picked up a full assembly for 185$.

Long story short they put it in and like magic my throttle pulse is gone and the gas gauge is now accurate.
The technican theorizes that the pump had restriction such that under moderate load it would stave the end injectors creating a lean trim condition on both banks. They also noted that typically when you have fuel pump problems you would expect the trim to increase, it was decreasing with these symptoms. They did not believe this would work Thank you internet.

This is issue was so annoying that i almost wanted to sell this car. So glad that it is fixed. I hope others with this issue find this post.

Keywords: Throttle pulse, Surge, hesitation, moderate load, 2,000 to 3,000 rpm, all gears...

 

[looking4lc]

Glad it got fixed.lots of 100 series are facing fuel pump issue but with different symptoms. Mine would get hot and shut off. Cools down for a bit then start up again. Will be replacing the fuel pump this week.

I found denso here with filter for 70$ which one did u get? Oem is about 200$.

 

[wplong1]

While I am certain it goes against every written and unwritten rule of internet forums, I have to resurrect a 5 year old thread...

THANK YOU!!! This described EXACTLY the problem we were having with our 2007 LC. Toyota was unable to identify the problem and no codes were thrown by the computer. I was literally getting the vehicle ready to sell and super frustrated. After replacing the fuel pump the pulsing was eliminated completely.

The fuel pump replacement is super easy. There is an excellent Youtube video which can be seen here (not mine, but indispensable in helping plan and complete the replacement):



I opted to purchase OEM parts including the pump, new clamps, new seal, new hose and also the fuel level sending unit (may as well while you are in there) for a total of about $450. Was quoted $1150 for parts and replacement of pump only at Toyota. Total time spent replacing the pump and fuel level sensor including removal of the rear seats and putting everything back together was approximately 1 hour. For anyone planning to tackle this, definitely depressurize the fuel system first (not shown in the video). A surprising amount of fuel will come out of the pressure side hose when you disconnect it. Also, the second row passenger side seat does NOT need to be removed. There is enough room to fold it forward and hold the carpeting out of the way.

The parts list for my 2007 LC was:

90467-12067 Clamp x2
23220-50160 Pump
23239-11010 hose
77169-33020 gasket
83320-60340 fuel level sender


Really hope someone else is saved/helped by this thread started by Thewjsand and that I was able to add a little.

 

[Trolling4Tuna]

Hate to resurrect (for a second time) this old thread, but I gotta add a THANK YOU to the OP for discussing this issue and @wplong1 for linking the vid. I've had the exact same problem since taking my '07 LX470 home 6 months ago (pre-purchase inspection didn't include a freeway drive so my guy missed it), and it's been driving me nuts. My local Toyo tech thought it might be the trans ($$$) but before I had him take her apart I stumbled across this thread. Sooo happy I did.

Picked up a complete pump assembly on eBay for $150 and swapped it out myself in 1.5hrs.

 

[2001LC]

If a used fuel pump, you may run into iusse.

06-07 have a known bad fuel pump. I've replace many. I did one a few days ago. In an 06LC w/250K. We actually did not have any of the classic symptom and they usually fail much earlier. Just did as a PM. But fuel trims after, are showing improvement.


Classic 06-07 fuel pump issues. After running in high RPM, like climbing a mountain pass. We let off the gas pedal dropping RPM, as we crest the top of pass and engine dies. This show up in summer heat, more than cooler days. What happens is fuel pump runs in a higher speed at high RPM. This generates more heat within it, than low speed stage. Which the heat creates more resistance in the fuel pump motor. As fuel pump switches to low speed, pump motor slow to much ( do to increased resistance from heat). Which reduces fuel flow. We get lean bk 1 & 2 at time of occurrence.