Sudden idle speed drop...
Thread Starter
Pit Crew
Joined: Mar 2012
Posts: 154
Likes: 22
From: NY
Sudden idle speed drop...
So.... my '06 started perfectly like it normally does but as I was putting my seat belt on and grabbing my sunglasses, suddenly it started to feel like it was going to stall. I watched the tach shaking and going lower and lower. Suddenly it jumped back up and idled as it should.
I backed out of the garage and let it warm up a little. Rev-ing the engine sounded and felt perfect.
I decided to take her for a drive... as I was pulling out of my development, she felt like she was going to stall so I pulled over. Just like before, the tach suddenly jumped back to where it should be.
I turned around and headed back home. Part way home the same thing happened but this time she stalled. I restarted her and put her in the garage...
There is no check engine light on and per the battery maintainer, it was fully charged before discontinued it and started her up. Fresh tank of gas the week before this happened and she drove find after that.
Has this happen to anyone else?
I backed out of the garage and let it warm up a little. Rev-ing the engine sounded and felt perfect.
I decided to take her for a drive... as I was pulling out of my development, she felt like she was going to stall so I pulled over. Just like before, the tach suddenly jumped back to where it should be.
I turned around and headed back home. Part way home the same thing happened but this time she stalled. I restarted her and put her in the garage...
There is no check engine light on and per the battery maintainer, it was fully charged before discontinued it and started her up. Fresh tank of gas the week before this happened and she drove find after that.
Has this happen to anyone else?
Pole Position
Joined: May 2016
Posts: 3,053
Likes: 631
From: AZ
My guess is one of your vacuum hoses cracked. Look under the hood and see if you see anything. google "site:clublexus.com sc430 cracked hose" and you can get a better idea of the problem I think it is
Thread Starter
Pit Crew
Joined: Mar 2012
Posts: 154
Likes: 22
From: NY
Last edited by Oldsig; Oct 18, 2023 at 02:57 PM.
Pole Position
Joined: May 2016
Posts: 3,053
Likes: 631
From: AZ
All the hoses age at about the same rate. I had a cracked hose that was obvious and a P0440 code. I replaced the hose and a couple days later I got another Check engine light. I ended up replacing all the hoses.
Since you do not have a CHECK ENGINE LIGHT, it maybe something else, like a bad MAF sensor.
Your best bet is to have your car scanned for codes and go from there. Though you may not have a check engine light now, the computer may have PENDING codes you can read.
Let us know what you find
Since you do not have a CHECK ENGINE LIGHT, it maybe something else, like a bad MAF sensor.
Your best bet is to have your car scanned for codes and go from there. Though you may not have a check engine light now, the computer may have PENDING codes you can read.
Let us know what you find
Thread Starter
Pit Crew
Joined: Mar 2012
Posts: 154
Likes: 22
From: NY
It's been at my local Toyota dealership for 2-days now. I got a call late in the day from them. They confirmed there are no codes. They also didn't find any cracked vacuum hoses (either).
They mainly called to see if I had anymore information on what's happening. It's a fairly short and simple story so all I could do was to tell them again and remind them I left a writeup sticking out of the center console.
The only good news is they haven't given up yet!
Oh, BTW, they can't duplicate the stalling or RPM dropping and suddenly popping back up to where it should be... that's the worst type of issue...
They mainly called to see if I had anymore information on what's happening. It's a fairly short and simple story so all I could do was to tell them again and remind them I left a writeup sticking out of the center console.
The only good news is they haven't given up yet!
Oh, BTW, they can't duplicate the stalling or RPM dropping and suddenly popping back up to where it should be... that's the worst type of issue...
Pole Position
Joined: May 2016
Posts: 3,053
Likes: 631
From: AZ
This is just a stab in the dark and probably not worth having them check it, but maybe your alternator is failing.When my alternator was going out, I was driving down the street and then my radio shut off, my car would seem to coast and then everything came back. BUT the only difference was my car died totally 2 miles later.
Possibly your alternator is intermittent. If it is the alternator, it does not leave a code. (mostly because it kills the power and your ecu resets)
Possibly your alternator is intermittent. If it is the alternator, it does not leave a code. (mostly because it kills the power and your ecu resets)
Pole Position
Joined: Oct 2015
Posts: 3,110
Likes: 614
From: CA
This is just a stab in the dark and probably not worth having them check it, but maybe your alternator is failing.When my alternator was going out, I was driving down the street and then my radio shut off, my car would seem to coast and then everything came back. BUT the only difference was my car died totally 2 miles later.
Possibly your alternator is intermittent. If it is the alternator, it does not leave a code. (mostly because it kills the power and your ecu resets)
Possibly your alternator is intermittent. If it is the alternator, it does not leave a code. (mostly because it kills the power and your ecu resets)
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Thread Starter
Pit Crew
Joined: Mar 2012
Posts: 154
Likes: 22
From: NY
I just got off the phone with the Service Advisor. He may have misspoke previous because now he says that it is "acting up" for him when he took it for a drive and for the Technician while he's doing debug. He thinks that it's worse or only does it when the engine is cold.... hmm...
He said there are no codes and they see nothing when it's acting like it's going to stall. I confirmed again they looked for vacuum leaks and did smoke tests (what I call them) but they found none.
The Technician found something online that it could be throttle body related. They cleaned and recalibrate it (and admitted that the voltage range was already correct) and the issue continues.
They now want to give up on it and said that maybe a Lexus dealership could find the issue. I explained that they would start by doing the same scans and maybe the same debug all over again. I also reminded them that I can't safely drive it anywhere and the closest Lexus dealership is almost 2 hours away.
He said they have a higher level Technician that can look at it in a few days so that's what I asked him to do...
Anything else I should suggest for them to look at?
He said there are no codes and they see nothing when it's acting like it's going to stall. I confirmed again they looked for vacuum leaks and did smoke tests (what I call them) but they found none.
The Technician found something online that it could be throttle body related. They cleaned and recalibrate it (and admitted that the voltage range was already correct) and the issue continues.
They now want to give up on it and said that maybe a Lexus dealership could find the issue. I explained that they would start by doing the same scans and maybe the same debug all over again. I also reminded them that I can't safely drive it anywhere and the closest Lexus dealership is almost 2 hours away.
He said they have a higher level Technician that can look at it in a few days so that's what I asked him to do...
Anything else I should suggest for them to look at?
Last edited by Oldsig; Oct 30, 2023 at 01:47 PM.
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Lexus Test Driver
Joined: Dec 2014
Posts: 8,213
Likes: 949
From: Fl
if so, then you might want to keep monitoring the battery & alternator.
if you have TechStream, you could hook it up and watch the alternator voltages
Advanced
Joined: Jul 2023
Posts: 554
Likes: 74
From: SC
Side thought... You said you just filled it up with fresh gas, I'm thinking bad gas or water in the gas maybe. You say it ran fine after the fill up, how far did you drive it? It'll take a bit to get from the tank to the motor. Again, just a thought.
Pole Position
Joined: Oct 2015
Posts: 3,110
Likes: 614
From: CA
I'm with you. It could be very well that water in the gas.
Thread Starter
Pit Crew
Joined: Mar 2012
Posts: 154
Likes: 22
From: NY
It's still at the dealership and although I do not have 100% of the information, they said that they "are monitoring everything while it is running and they see no changes when it acts like it is going to stall". In the same conversation multiple times they mentioned Techstream being connected.
Thread Starter
Pit Crew
Joined: Mar 2012
Posts: 154
Likes: 22
From: NY
Keep the thoughts and ideas coming 🙂
