LS Stalled Out, Where to start?
Thread Starter
Racer
Joined: Jan 2011
Posts: 1,761
Likes: 248
From: AZ
LS Stalled Out, Where to start?
My 04 LS430 stalled out on me.
It's been a while since I've had a car simply break down and had to get a tow truck.
Car drove fine, I came to a stop, pressed the accelerator pedal and she stalled out. I tried to restart, it cranked over fine, would maybe idle a half second then stall out again. I would wait, try it again a few minutes later, basically the same thing. Battery is relatively new, and no problems turning over. No codes have ever been thrown.
The car had been left alone for a few hours, went out and it started up just fine.
I'm going to clean the throttle body and MAF sensor this weekend. Any other areas to look at? I hate "shotgunning" parts at a car, but I may throw on a new TPS sensor on it since it's only about what I pay for a tank of gas.
I would think if it was ignition related, it would throw some codes. My fear is it needs a new fuel pump.
I hate coming into a dealership with an issue like, they're going to want to just start throwing expensive parts at it.
Any advice would be appreciated.
It's been a while since I've had a car simply break down and had to get a tow truck.
Car drove fine, I came to a stop, pressed the accelerator pedal and she stalled out. I tried to restart, it cranked over fine, would maybe idle a half second then stall out again. I would wait, try it again a few minutes later, basically the same thing. Battery is relatively new, and no problems turning over. No codes have ever been thrown.
The car had been left alone for a few hours, went out and it started up just fine.
I'm going to clean the throttle body and MAF sensor this weekend. Any other areas to look at? I hate "shotgunning" parts at a car, but I may throw on a new TPS sensor on it since it's only about what I pay for a tank of gas.
I would think if it was ignition related, it would throw some codes. My fear is it needs a new fuel pump.
I hate coming into a dealership with an issue like, they're going to want to just start throwing expensive parts at it.
Any advice would be appreciated.
Driver School Candidate
Joined: Apr 2011
Posts: 25
Likes: 0
From: fl
The tps is fine. Tps will throw codes. Try cleaning your maf and throttle body. Disconnect the battery for 5 min to reset the idle. Ive never heard of a bad tps or fuel on a ls430. Also ck and see if its not overheating cus it will shutoff if the car overheats. Btw im a lexus tech just to let u know. Let me know how it goes.
Intermediate
Joined: Sep 2002
Posts: 289
Likes: 9
From: Georgia
If the car won't start how is he to know if the check engine light is on? You will have to get it scanned to see if there is a code. Sounds to me like you might have a fuel related issue. Check the fuel pump relay 1st.
Pole Position
Joined: Nov 2006
Posts: 278
Likes: 7
From: TX
If your car runs fine but stalls at stops more than likely the idle throttle need to be cleaned, the best way is remove the hose came from air filter box connected to the idle throttle body, spray a bunch of carburator cleaner on a clean rag then flip the flap, reach in as far as you can, repeat cleaning and that should fix the problem.
Thread Starter
Racer
Joined: Jan 2011
Posts: 1,761
Likes: 248
From: AZ
The tps is fine. Tps will throw codes. Try cleaning your maf and throttle body. Disconnect the battery for 5 min to reset the idle. Ive never heard of a bad tps or fuel on a ls430. Also ck and see if its not overheating cus it will shutoff if the car overheats. Btw im a lexus tech just to let u know. Let me know how it goes.
The reason I was looking at the TPS being an issue is I had a car before with a similar issue where it needed to be replaced, it was almost like the fuel just being cut off.
BTW, in your response you said you've never heard of a "bad fuel" did you mean "bad fuel pump"? If so, that's a relief.
Car wasn't overheating, temp gauge was where it always is.
I'm going to start with cleaning the Throttle body and mass air.
The only other issue that may be related is I sometimes get the sulphur smell from my exhaust, but it sounds like that's a pretty common issue with this generation LS.
The car started up fine and I was able to put it in my garage. No error codes came up.
Thanks again.
Thread Starter
Racer
Joined: Jan 2011
Posts: 1,761
Likes: 248
From: AZ
Cleaned out the Mass Air and the throttle body and unplugged the battery overnight. So far so good, it seems to idle and drive a lot smoother, but that could just be in my head. It hasn't stalled out since.
The Mass Air sensor looked like it had been dipped in black paint before I cleaned it. The throttle body was also dirty as well, but I'm betting the mass air was the main culprit.
I'd definitely recommend doing this service, even if you're not having issues. Don't wait until it leaves you stranded, it's very easy for the DIY'er to tackle, not much more difficult than changing an air filter.
The Mass Air sensor looked like it had been dipped in black paint before I cleaned it. The throttle body was also dirty as well, but I'm betting the mass air was the main culprit.
I'd definitely recommend doing this service, even if you're not having issues. Don't wait until it leaves you stranded, it's very easy for the DIY'er to tackle, not much more difficult than changing an air filter.
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2nd gear
Joined: Mar 2025
Posts: 2
Likes: 0
Did you figure it out?
did you figure it out? I’m having the same exact problem happening right now I can only get it started if I press the gas a couple times as I start it other wise it just stalls I’ve replaced the fuel pump and maf sensor next thing that I’ve read that can help is the fuel filter. If you have any suggestions let me know
Driver
Joined: Feb 2024
Posts: 60
Likes: 5
From: Ohio
Is it staying running and running fine as long as you're moving? Also is the check engine light on at all? Are you able to get it running once it starts stalling by giving it more throttle?
Last edited by Duowing; Mar 28, 2025 at 02:30 PM.
2nd gear
Joined: Mar 2025
Posts: 2
Likes: 0
.
yes I can get it started if I give it allot of throttle and drive it but no it doesn’t drive normal when I do that it has a major lack of power so I haven’t been driving it like that I just started it up and drove it to the mechanic shop but they couldn’t figure it out, yes it does have a check engine like I pulled the codes and 1 code has been on for a minute for the knock sensors but u don’t think that would cause my car to stall, there’s also a code for the maf sensor so I got a new one and it still doesn’t work.
Instructor
Joined: Apr 2017
Posts: 1,245
Likes: 189
From: Texas
BradTank, your fuel pump in the gas tank is going bad! Its cheaper than the high pressure pump but harder to DIY. Been there done that, Mine would work for a week then stall in an intersection in heavy traffic! The third time it did it my new wife was in the car and was she ever pissed!
Last edited by jimisbell; Mar 31, 2025 at 04:17 PM.
Pit Crew
Joined: Oct 2020
Posts: 149
Likes: 27
From: Ontario
My 04 LS430 stalled out on me.
It's been a while since I've had a car simply break down and had to get a tow truck.
Car drove fine, I came to a stop, pressed the accelerator pedal and she stalled out. I tried to restart, it cranked over fine, would maybe idle a half second then stall out again. I would wait, try it again a few minutes later, basically the same thing. Battery is relatively new, and no problems turning over. No codes have ever been thrown.
The car had been left alone for a few hours, went out and it started up just fine.
I'm going to clean the throttle body and MAF sensor this weekend. Any other areas to look at? I hate "shotgunning" parts at a car, but I may throw on a new TPS sensor on it since it's only about what I pay for a tank of gas.
I would think if it was ignition related, it would throw some codes. My fear is it needs a new fuel pump.
I hate coming into a dealership with an issue like, they're going to want to just start throwing expensive parts at it.
Any advice would be appreciated.
It's been a while since I've had a car simply break down and had to get a tow truck.
Car drove fine, I came to a stop, pressed the accelerator pedal and she stalled out. I tried to restart, it cranked over fine, would maybe idle a half second then stall out again. I would wait, try it again a few minutes later, basically the same thing. Battery is relatively new, and no problems turning over. No codes have ever been thrown.
The car had been left alone for a few hours, went out and it started up just fine.
I'm going to clean the throttle body and MAF sensor this weekend. Any other areas to look at? I hate "shotgunning" parts at a car, but I may throw on a new TPS sensor on it since it's only about what I pay for a tank of gas.
I would think if it was ignition related, it would throw some codes. My fear is it needs a new fuel pump.
I hate coming into a dealership with an issue like, they're going to want to just start throwing expensive parts at it.
Any advice would be appreciated.