Engine Or Transmission Causing "chugging?"

[amcdonal86]

My 94LS has the same "jerky" problem at around 45 mph. It's not getting better or worse, it just is always there. Seems like a tranny thing. But since the A/C went out at the end of the Summer (and I live in Vegas, whew), and that now there is a slight rat-a-tat sound when just starting to accelerate and then when stopping, I think the LS is ready for dismissal. I'm going to drive it to its end, and then buy a Kia, or a Honda, or a Fisker Karma (I wish). Sad, a beautiful car, bought it with 97,000 miles, only 119,000 miles now, but there comes a time when you must say goodbye to an old friend. Best highway cruiser ever....

Maybe it just needs an oil change and a tune up! Don't give up so fast! 120k miles is pretty low mileage for these cars.

[JeffreyV]

I used a wire to check for engine and transmission codes after work today. All I saw was rapidly and consistently flashing Check Engine and O/D Lights. OK - no problems stored in the computer. So, I decided to clean the throttle body. I sprayed it until it was spotless then oiled the shafts of the butterfly inside the throttle body. A 20 mile drive and no jerking whatsoever. I think it might be too good to be true. But I came across a 19 page explanation of the TOYOTA ELECTRONIC CONTROL TRANSMISSION today. Wow, it explains everything about shifting, lock-up, etc. It also said "says “The throttle position sensor (connected to the throttle body) gives the Electronic Control Unit an indication of engine load to control shifting and lock-up timing.” Hmmmmm??? It says that Toyota's lock-up works in all gears except first... If the shifter is in "D" position. It also talkes about the water temp sensor which prevents shifting into O/D or lock-up until the coolant reaches a predetermined temp. If anyone wants a copy, I'll scan it. email me at byerjv@yahoo.com.

This is fantastic news! I hope the problem doesn't come back.

Please keep us posted if it does!

Another 30 miles today on a smooth, level road running at 55 to 60mph... no jerking. It used to start jerking at 45mph... I think it was the lock-up feature trying to engage. Now at 45 I can't feel anything, but can watch the rpm drop. I attribute it to cleaning the throttle body. WELL, I SPOKE TOO SOON. THE COLD WEATHER RETURNED AND THE CAR IS JERKING AGAIN AT AROUND 40 - 55 MPH. I READ THAT SOMEONE ELSE HAD THIS PROBLEM AND FINALLY AFTER A FEW YEARS OF REPLACING NUMEROUS ENGINE TUNE UP PARTS TO NO AVAIL, INSTALLED A NEW TORQUE CONVERTED AND IT SOLVED THE JERKING PROBLEM. I THINK I'LL HAVE TO DO THE SAME. byerjv@yahoo.com

[CanadaCraig]

Hi Everyone!! :)

I hope you're OK.

I have to admit - this is a VERY interesting topic for me. I've had that 'chugging' problem ever since I bought my 1993 LS400 in October of 2003. I have often described the feeling as if I was towing something. [And the weight of the imaginary thing trailing behind me was jerking the car as the wind hits 'it' - or something like that] A Lexus troubleshooter finally figured out [After I had already replaced several parts and cleaned the throttle body, etc., etc.] that it was a problem with my torque converter. He said [And this is going back a couple of years now - but my car still has the same problem because I can't afford to buy a new TC] that if I press on the brake pedal just enough to cause the brake lights to go ON [Which you can see - when it's dark out at least - in your rear view mirror as the third brake light reflects on the back window] the TC clutch will UNLOCK. When MY car is 'chugging' or 'jerking' at around 80 km/h [50 MPH] and I cause the brake lights to come on - the 'chugging' and/or 'jerking' instantly STOPS.

That said..... just around town - the car is fine - for the most part. And can accelerate quite quickly. But once the clutch starts to act up - the power from the engine TO the transmission is noticeably and negatively effected. [Or is that affected - I can never figure that out!!]

If you're still having the same problem - try that - and see what happens.

That said - I'd love to know if it's possible to unplug something and keep the TC clutch from engaging.

Craig!! :)

[90LS400Lexus]

My 1991 (218K) is still doing it as well. Yes, it kinds feels like you are towing a small trailer and its bumping the car back and forward at certain speeds. I am not yet ruling out the engine/transmission mounts though since they are still the originals @ nearly 220K and I am also getting horrid vibrations!

If its the torque converter causing this "bumping" issue, I am NOT fixing it... I cant even imagine how many Ben Franklins (thats 100 dollar bills for you that dont live in the states) that will cost to repair on this junkyard fodder. I will sell it, junk it, donate it to charity and take a $4000 loss and give the Mercedes rather than the Lexus to my mother and buy me another car. I could have bought a nice 2001 LS for what I have spent/going to spend in repairs on this car!

Alot of people always says what "excellent" transmissions these cars have, but seems like I read alot about these torque converter issues lately. I hope thats not mine (or anyone elses here) problems.

I hate to have to complain and be a downer all of the time, but this car is really bumming me out. Seems like when I get one thing fixed, there is something else to replace. IF I can ever get ahead (this car is driving me to bankruptcy), I will replace the engine/transmission mounts and see if this clears up most of my problems (as some here have said it may).

Hi Everyone!! :)

I hope you're OK.

I have to admit - this is a VERY interesting topic for me. I've had that 'chugging' problem ever since I bought my 1993 LS400 in October of 2003. I have often described the feeling as if I was towing something. [And the weight of the imaginary thing trailing behind me was jerking the car as the wind hits 'it' - or something like that] A Lexus troubleshooter finally figured out [After I had already replaced several parts and cleaned the throttle body, etc., etc.] that it was a problem with my torque converter. He said [And this is going back a couple of years now - but my car still has the same problem because I can't afford to buy a new TC] that if I press on the brake pedal just enough to cause the brake lights to go ON [Which you can see - when it's dark out at least - in your rear view mirror as the third brake light reflects on the back window] the TC clutch will UNLOCK. When MY car is 'chugging' or 'jerking' at around 80 km/h [50 MPH] and I cause the brake lights to come on - the 'chugging' and/or 'jerking' instantly STOPS.

That said..... just around town - the car is fine - for the most part. And can accelerate quite quickly. But once the clutch starts to act up - the power from the engine TO the transmission is noticeably and negatively effected. [Or is that affected - I can never figure that out!!]

If you're still having the same problem - try that - and see what happens.

That said - I'd love to know if it's possible to unplug something and keep the TC clutch from engaging.

Craig!! :)

[JeffreyV]

I asked because sometimes when mine is in overdrive around those speeds and I quickly release the accelerator and press it quick again, it will kinda jerk a couple of times, but I was assuming it was from my completely worn out engine mounts and transmission mount allowing slack to cause that.

Otherwise my transmission shifts flawlessly and smoothly through all gears.

I'm still having problems with the car "jerking" when the lock-up feature of the torque converter tries to engage at about 45mph. It comes and goes. Last week the car was fine, but it's been chugging again for four days now!!! I'm considering just disconnecting the electronic lock-up feature. Does anyone know exactly where it's located on a 1992 LS400? Is it attached outside the transmission? Is it easily disconnected? Thank you!

[JeffreyV]

My 1991 (218K) is still doing it as well. Yes, it kinds feels like you are towing a small trailer and its bumping the car back and forward at certain speeds. I am not yet ruling out the engine/transmission mounts though since they are still the originals @ nearly 220K and I am also getting horrid vibrations!

If its the torque converter causing this "bumping" issue, I am NOT fixing it... I cant even imagine how many Ben Franklins (thats 100 dollar bills for you that dont live in the states) that will cost to repair on this junkyard fodder. I will sell it, junk it, donate it to charity and take a $4000 loss and give the Mercedes rather than the Lexus to my mother and buy me another car. I could have bought a nice 2001 LS for what I have spent/going to spend in repairs on this car!

Alot of people always says what "excellent" transmissions these cars have, but seems like I read alot about these torque converter issues lately. I hope thats not mine (or anyone elses here) problems.

I hate to have to complain and be a downer all of the time, but this car is really bumming me out. Seems like when I get one thing fixed, there is something else to replace. IF I can ever get ahead (this car is driving me to bankruptcy), I will replace the engine/transmission mounts and see if this clears up most of my problems (as some here have said it may).

Hi Everyone!! :)

I hope you're OK.

I have to admit - this is a VERY interesting topic for me. I've had that 'chugging' problem ever since I bought my 1993 LS400 in October of 2003. I have often described the feeling as if I was towing something. [And the weight of the imaginary thing trailing behind me was jerking the car as the wind hits 'it' - or something like that] A Lexus troubleshooter finally figured out [After I had already replaced several parts and cleaned the throttle body, etc., etc.] that it was a problem with my torque converter. He said [And this is going back a couple of years now - but my car still has the same problem because I can't afford to buy a new TC] that if I press on the brake pedal just enough to cause the brake lights to go ON [Which you can see - when it's dark out at least - in your rear view mirror as the third brake light reflects on the back window] the TC clutch will UNLOCK. When MY car is 'chugging' or 'jerking' at around 80 km/h [50 MPH] and I cause the brake lights to come on - the 'chugging' and/or 'jerking' instantly STOPS.

That said..... just around town - the car is fine - for the most part. And can accelerate quite quickly. But once the clutch starts to act up - the power from the engine TO the transmission is noticeably and negatively effected. [Or is that affected - I can never figure that out!!]

If you're still having the same problem - try that - and see what happens.

That said - I'd love to know if it's possible to unplug something and keep the TC clutch from engaging.

Craig!! :)

YES, IT STOPS CHUGGING/JERKING IF I PUT THE BREAK ON AND MAINTAIN 45 MPH USING THE GAS PEDAL. IF I TAKE MY FOOT OFF THE BREAK IT STARTS CHUGGING AGAIN. THAT'S WHAT I'D LIKE TO DO... DISCONNECT THE LOCK UP FEATURE OF THE TORQUE CONVERTER. I'M THINKING I'LL ASK MY MECHANIC. HAVE YOU TRIED DISCONNECTING IT YET?

[VBdenny]

Nobody seemd to ask if the R (reverse) light comes on when you use the brakes. If this is the case, it is a simple fix. Mine did exactly the same thing and it was caused by a broken wire in the trunk hinge. I spliced in a new section and everything was back to normal. Just a thought.

[HomerTHX1138]

Mine did this when I got it (used), right around 45mph. It also hesitated off the line under light throttle.

I did a lot of maintenace, so it could have been a combination of many things but having the transmission fluid and filter replaced, cleaning the throttle body and having a tune up including new spark plugs and wires made it go away. The throttle body was the biggest improvement but the tune up finished the job.

[90LS400Lexus]

Well, my '91 is still doing this and I hope with the tranny mount I am soon replacing will stop alot of it. If not, I am going to have the throttle body replaced and see if thats it. Mine seems to do it worse during the first 4 to 5 miles of driving when first driven for the day. I do also get that momentarily hesitation when I first accelerate too though. The car pulled out, it hits 1200 rpms, its like it hold back/hits a dead spot, then takes off again. Dont know if the problems are related though.

[foxfire]

I have a 1991 LS 400 with 130K that has shown similar problems lately. I found this thread because I need to fix it, it is driving me crazy. About six months ago I replaced the power steering pump and had the alternator rebuilt. In the process I cleaned the throttle body and of course disconnected a few other things. Since then the missing or "chugging" has been pretty consistent throughout the gears and I have found that it does it less if I turn the overdrive button off. This changes the rpms (although I havent fixed the tach yet) you can feel it.

I always thought that it was fuel related, electrical or sensor related or that maybe moisture got into something when I cleaned the engine. I have run seafoam and other stuff to try and clean it but nothing. The only thing that helps is the overdrive. Sadly it makes me want to drive faster to keep it from missing which isnt good. I never thought about the transmission or tourque converter. I would be interested also in un hooking and seeing what happens. Any response to where the sensor is located? thanks for any advice

[90LS400Lexus]

I have a 1991 LS 400 with 130K that has shown similar problems lately. I found this thread because I need to fix it, it is driving me crazy. About six months ago I replaced the power steering pump and had the alternator rebuilt. In the process I cleaned the throttle body and of course disconnected a few other things. Since then the missing or "chugging" has been pretty consistent throughout the gears and I have found that it does it less if I turn the overdrive button off. This changes the rpms (although I havent fixed the tach yet) you can feel it.

I always thought that it was fuel related, electrical or sensor related or that maybe moisture got into something when I cleaned the engine. I have run seafoam and other stuff to try and clean it but nothing. The only thing that helps is the overdrive. Sadly it makes me want to drive faster to keep it from missing which isnt good. I never thought about the transmission or tourque converter. I would be interested also in un hooking and seeing what happens. Any response to where the sensor is located? thanks for any advice

Well, mine is still doing it and honestly, it feels like the torque converter to me, but I hope not... I am hoping its either the tranny mount, or the throttle body. My transmission shifts smoothly in all gears, even when going into and out of lockup mode. Its mainly when changing between an incline or decline on light acceleration... it kinda jerks back and forth, almost like a bobble. :(

[cappakazi]

Hey just read this topic and well guess what exact same symptoms but in my car ls400 89 (celsior) i get the engine light and the trc off light goes on. At first it wasnt that bad, but now my car stalls at the lights. Sure its the torque convertors? anyone fixed it and found it is the answer?

oh and also i cant turn the trc on or off when its in this state too.

[90LS400Lexus]

Hey just read this topic and well guess what exact same symptoms but in my car ls400 89 (celsior) i get the engine light and the trc off light goes on. At first it wasnt that bad, but now my car stalls at the lights. Sure its the torque convertors? anyone fixed it and found it is the answer?

oh and also i cant turn the trc on or off when its in this state too.

AFAIK, no one is really sure yet. I am not getting the engine light issue and my car dont have trac control, so I am not sure about that. I am going to try to get my throttle body cleaned soon and a new tranny mount and see what happens... if OK, then onto getting the PS leak repaired. Useless piece of junkyard fodder.

[cappakazi]

Hey just read this topic and well guess what exact same symptoms but in my car ls400 89 (celsior) i get the engine light and the trc off light goes on. At first it wasnt that bad, but now my car stalls at the lights. Sure its the torque convertors? anyone fixed it and found it is the answer?

oh and also i cant turn the trc on or off when its in this state too.

AFAIK, no one is really sure yet. I am not getting the engine light issue and my car dont have trac control, so I am not sure about that. I am going to try to get my throttle body cleaned soon and a new tranny mount and see what happens... if OK, then onto getting the PS leak repaired. Useless piece of junkyard fodder.

Just too let you know that in Australia these cars are going for about$10k private sales and from a import dealer $13-15k. Not chump change lol

Msut be different scenario in the US.

[90LS400Lexus]

Hey just read this topic and well guess what exact same symptoms but in my car ls400 89 (celsior) i get the engine light and the trc off light goes on. At first it wasnt that bad, but now my car stalls at the lights. Sure its the torque convertors? anyone fixed it and found it is the answer?

oh and also i cant turn the trc on or off when its in this state too.

AFAIK, no one is really sure yet. I am not getting the engine light issue and my car dont have trac control, so I am not sure about that. I am going to try to get my throttle body cleaned soon and a new tranny mount and see what happens... if OK, then onto getting the PS leak repaired. Useless piece of junkyard fodder.

Just too let you know that in Australia these cars are going for about$10k private sales and from a import dealer $13-15k. Not chump change lol

Msut be different scenario in the US.

Even for a 90-94 LS/Celsior? They wanna buy mine for $4K?

[JeffreyV]

Well, my '91 is still doing this and I hope with the tranny mount I am soon replacing will stop alot of it. If not, I am going to have the throttle body replaced and see if thats it. Mine seems to do it worse during the first 4 to 5 miles of driving when first driven for the day. I do also get that momentarily hesitation when I first accelerate too though. The car pulled out, it hits 1200 rpms, its like it hold back/hits a dead spot, then takes off again. Dont know if the problems are related though.

After new spark plug wires, distributer caps and new throttle position sensor, my engine missing/chugging at 45-50 mph disappeared for 2 months. It has come back (but not nearly as bad) with the cold weather (40 degrees in the morning). I'm thinking it could be the thermistor which monitors the coolant temperature and once warm enough allows the transmission to shift into overdrive or the converter to go into lock-up. I think I'll let the car idle for 15 minutes before I drive and see if it still misses/chugs. Maybe the throttle position sensor setting has changed and needs to be reset. At any rate, my normal car mechanic is good and won't work on a Lexus. He says you fix one thing and something else breaks. I think this is the last Lexus I'll own. I like the car, but it's aggravating.

[90LS400Lexus]

After new spark plug wires, distributer caps and new throttle position sensor, my engine missing/chugging at 45-50 mph disappeared for 2 months. It has come back (but not nearly as bad) with the cold weather (40 degrees in the morning). I'm thinking it could be the thermistor which monitors the coolant temperature and once warm enough allows the transmission to shift into overdrive or the converter to go into lock-up. I think I'll let the car idle for 15 minutes before I drive and see if it still misses/chugs. Maybe the throttle position sensor setting has changed and needs to be reset. At any rate, my normal car mechanic is good and won't work on a Lexus. He says you fix one thing and something else breaks. I think this is the last Lexus I'll own. I like the car, but it's aggravating.

AMEN to those last two sentences you posted! Me too! I used to love my car, but all of these little annoyances that I cant repair myself, or cant afford to repair myself is so disappointing. Last LS I owned I said I would never own another, then I took a chance and bought this one. Fool I am. I honestly dont think I will ever buy another... not a gen 1 with high miles. If I ever do buy one, it will be a 2001-02 LS430 with good miles, but it will be awhile before I can afford that.

Anyway, there is another person on another Lexus site that mentions this issue. His LS is in the shop as we speak. He thinks its the transmission, so its in a transmission shop to be checked and will report back. I mentioned that I was most interested because his symptoms sounded like the issues I have. I will post his results.

I thought new transmission mount would help mine, but it didnt. I still even get that gear shifter "shake" at certain times at highway speeds, so I am at a loss as to whats going on (my Mercedes shifter is a still as a frog on a lilly pad lol.). I still get that "chug" or jerk on light acceleration as the grade of the road changes. I have been told it could be the throttle body needs cleaning, so I am going to have that done and see. My main concern now is the big loss of power steering assist (I have very little assist from the power steering). Most recently my car has started that ever-so-dreaded "clunking" from the front suspension on certain bumps in the road. It is so annoying and my last LS did this since day 1 I owned it and I really hated it. Seems like as soon as my car hit 224K, this started, which was the same mileage my old LS had about the time I bought it.

As I have said before the plan was to sell this car to my mom, but I am not sure I would pack this car off on her, but she still seems to think its a good car, but I would rather her buy my Mercedes and me sell the LS and buy me something else.

We will see. Good luck with your car, hopefully you can get yours up to par. I think mine is too car gone (for ME to bring back) and it only has 224K miles. <_< I am sure that someone with the ability or money to get it back up to standard would enjoy this otherwise fine car. ;)

[ehabmarco]

Very old post but I see it worth posting as the problem was not fixed here

I Had this same problem for months till reaching the cause

It was the oxygen sensor that was causing this hesitation when cruising

["95 LS400]

Hi first time on here but anyways I have 95 ls400 and when cruising at 40 to 50 I'm getting a chugging feel I feel like its my transmission so I'm going to try to find one cheap. Y would it be the oxygen sensor????