Changing down gear too readily
Thread Starter
Driver School Candidate
Joined: Dec 2020
Posts: 6
Likes: 2
From: Hampshire
Changing down gear too readily
I am finding my 2005 LS430 is dropping a gear for the slightest acceleration and seems to forget it's a torquey V8.
For example, on a flat at 65mph if I "resume" cruise control to 75mph, it'll drop from 6th to 5th.
Worse, on a very slight incline it'll drop to 4th for the same 65-75 increase.
I would expect a luxury car with such a strong engine to hold its gear. Is what I'm experincing normal, or should the car muscle through?
Jeremy
For example, on a flat at 65mph if I "resume" cruise control to 75mph, it'll drop from 6th to 5th.
Worse, on a very slight incline it'll drop to 4th for the same 65-75 increase.
I would expect a luxury car with such a strong engine to hold its gear. Is what I'm experincing normal, or should the car muscle through?
Jeremy
Instructor
Joined: Jan 2018
Posts: 965
Likes: 299
From: WA
What you are experiencing is not normal at least as far as slight incline. Is the ECT button above the gear selector **** in the middle (normal) position? If it was in the "power" position it will shift earlier.
My '05 virtually never downshifts to 4th and will hold 6th or 5th up a 5-6 percent grade at 50-60 mph, like a diesel.
My '05 virtually never downshifts to 4th and will hold 6th or 5th up a 5-6 percent grade at 50-60 mph, like a diesel.
Lexus Champion
Joined: Oct 2019
Posts: 18,096
Likes: 1,740
From: Ohio
If you are in pwr mode then it will prefer to shift down to be ready for speed increases whenever it senses and incline. It's not a bad thing that it shifts down and if you are using more than very light pedal it will so that's it's ready
Driver
Joined: Aug 2018
Posts: 54
Likes: 13
From: Il
I am finding my 2005 LS430 is dropping a gear for the slightest acceleration and seems to forget it's a torquey V8.
For example, on a flat at 65mph if I "resume" cruise control to 75mph, it'll drop from 6th to 5th.
Worse, on a very slight incline it'll drop to 4th for the same 65-75 increase.
I would expect a luxury car with such a strong engine to hold its gear. Is what I'm experincing normal, or should the car muscle through?
Jeremy
For example, on a flat at 65mph if I "resume" cruise control to 75mph, it'll drop from 6th to 5th.
Worse, on a very slight incline it'll drop to 4th for the same 65-75 increase.
I would expect a luxury car with such a strong engine to hold its gear. Is what I'm experincing normal, or should the car muscle through?
Jeremy
Thread Starter
Driver School Candidate
Joined: Dec 2020
Posts: 6
Likes: 2
From: Hampshire
What you are experiencing is not normal at least as far as slight incline. Is the ECT button above the gear selector **** in the middle (normal) position? If it was in the "power" position it will shift earlier.
My '05 virtually never downshifts to 4th and will hold 6th or 5th up a 5-6 percent grade at 50-60 mph, like a diesel.
My '05 virtually never downshifts to 4th and will hold 6th or 5th up a 5-6 percent grade at 50-60 mph, like a diesel.
I do also have what seems like a rich running engine as the exhaust smell is a little fruity and I have a high idle until fully warm - I wonder whether that may be closer to the root of the problem... I'll keep exploring.
Instructor
Joined: Jan 2018
Posts: 965
Likes: 299
From: WA
^ I would try to sort out the rich running engine first, then see if the transmission issue persists. Check for stored codes, inspect your air filter, clean the MAF filter, pull a spark plug and inspect, etc.
Thread Starter
Driver School Candidate
Joined: Dec 2020
Posts: 6
Likes: 2
From: Hampshire
I've replaced air filter (as part of an oil service), replaced the MAF with another from a good car, replaced the spark plugs and cleaned the throttle body. No joy.
My next step will be to remove the throttle body completely and have a go and the small idle holes, replacing the gaskets as I go.
After that I'm stumped.... perhaps a leaky injector? I have no codes at all, clean as a whistle, frustratingly!
Cheers,
Jeremy
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Instructor
Joined: Dec 2015
Posts: 878
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From: Arizona
Do you know it's running rich or are you just going by smell? A cheap $100 or less scanner will give you live data so you can observe short and long term fuel trims and know for sure. Hard data is better than assumptions.
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Advanced
Joined: Dec 2017
Posts: 716
Likes: 168
From: FL
I think I’ve found the cause of my high idle and rich running... slight exhaust leak! New gaskets ordered... hope this settles things.
https://youtu.be/TwfS0cJUo5E
https://youtu.be/TwfS0cJUo5E
Are you planning to change gaskets by yourself or at the station?
Thread Starter
Driver School Candidate
Joined: Dec 2020
Posts: 6
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From: Hampshire
I'm waiting for the gasket in shipping - but did put some exhaust repair paste on temporarily to see what the effect would be. Immediate improvement for a day... and then it managed to blow a hole through the patch and back to behaving as it was before 
Anyway, that confirms it is the cause of the poor running - so when the gasket and bolts finally turns up, I am expecting a good result!
Anyway, that confirms it is the cause of the poor running - so when the gasket and bolts finally turns up, I am expecting a good result!
Advanced
Joined: Dec 2017
Posts: 716
Likes: 168
From: FL
I'm waiting for the gasket in shipping - but did put some exhaust repair paste on temporarily to see what the effect would be. Immediate improvement for a day... and then it managed to blow a hole through the patch and back to behaving as it was before
Anyway, that confirms it is the cause of the poor running - so when the gasket and bolts finally turns up, I am expecting a good result!
Anyway, that confirms it is the cause of the poor running - so when the gasket and bolts finally turns up, I am expecting a good result!
They used stethoscope to do a quick check up of exhaust manifold and other areas. They didn’t find anything, however, one genius came and said that all two catalytic converters are blocked. They claimed that 430 F temperature is a direct indication of this fact. I asked them if they are 100 percent sure, for which they said they have no doubt. I asked if they see something else that could indicate their statement is true. No other tests were performed.
I wonder if what they said is true. Any insights will be appreciated.
CL Community Team
Joined: Dec 2005
Posts: 2,703
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From: 565 St Peter NOLA
Something interesting happened today. On my way home I decided to stop by at the exhaust shop to have them check if there is any exhaust leaks in my car.
They used stethoscope to do a quick check up of exhaust manifold and other areas. They didn’t find anything, however, one genius came and said that all two catalytic converters are blocked. They claimed that 430 F temperature is a direct indication of this fact. I asked them if they are 100 percent sure, for which they said they have no doubt. I asked if they see something else that could indicate their statement is true. No other tests were performed.
I wonder if what they said is true. Any insights will be appreciated.
They used stethoscope to do a quick check up of exhaust manifold and other areas. They didn’t find anything, however, one genius came and said that all two catalytic converters are blocked. They claimed that 430 F temperature is a direct indication of this fact. I asked them if they are 100 percent sure, for which they said they have no doubt. I asked if they see something else that could indicate their statement is true. No other tests were performed.
I wonder if what they said is true. Any insights will be appreciated.
