Low idle issue, with a twist
I have a 430 also. Same thing is happening. I don't think it's the engine mounts. Engine mounts would couse a car to stall. It is something more mechanical. I am thinking throttle pedal position sensor. If only I could get one cheap to test, it would be great, but I'm thinking I will just bite the bullet and change this before the summer.
The shakes only happen in gear (drive) on both my SC430 and GS430 when the engine has warmed up. We are talking about warm + 5 minutes of driving. When stopped, you notice a deffinate vibration. Put it into Park, and it gets much better, nearly gone. It seams that there must be a computer that should compensate for trany load, but fails to do so. You notice a deffinate RPM drop whan in gear.
Thread Starter
Lead Lap
Joined: Apr 2004
Posts: 3,565
Likes: 48
From: Illinois
Thread Starter
Lead Lap
Joined: Apr 2004
Posts: 3,565
Likes: 48
From: Illinois
Right, but you didn't post the number we're looking for -- car warmed up, everything off, car in gear, brake on and not moving. The only number you posted with everything off (including the the lights off) was the car warm and in park -- "Lights off, 775 in park warm".
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Pole Position
Joined: Oct 2005
Posts: 366
Likes: 0
From: IA
47 degrees and foggy 
engine hot
in gear
brake on
not moving
climate controls in the off position
no lights ~450 - engine does seem to bog down and has a very very small shake to it.
lights on - 600 - engine is smooth
I then put the car in park
no lights - 700
lights on - 700
I did notice that when turning the lights on it rose up fast, but when I turned the lights off it took a little bit to get down to the final RPMS.
Now my car has ~56K on it and the first ~44K were all older adult driving and about 95% highway miles, this car was a garage queen.
I'm leaning toward engine mounts being bad.
engine hot
in gear
brake on
not moving
climate controls in the off position
no lights ~450 - engine does seem to bog down and has a very very small shake to it.
lights on - 600 - engine is smooth
I then put the car in park
no lights - 700
lights on - 700
I did notice that when turning the lights on it rose up fast, but when I turned the lights off it took a little bit to get down to the final RPMS.
Now my car has ~56K on it and the first ~44K were all older adult driving and about 95% highway miles, this car was a garage queen.
I'm leaning toward engine mounts being bad.
Ok, but how can engine mounts keep your RPMs at or below 600 rpm. It just doesn't make sence. And other users report the RPMs falling so much that the car shuts off. I don't think it is the engine mounts.
Lexus Fanatic
Joined: Aug 2004
Posts: 6,947
Likes: 4
From: Florida
the question is do new mounts decrease the shaking, not increase the rpms.
Lexus Test Driver
Joined: Feb 2001
Posts: 1,590
Likes: 4
From: Bay Area
definitely one of the more annoying thing in this car.
I have had the low idle shake since the cars was about a year old.
Gs400 2000 with K/N drop in filter.
The gas mileage is crazy though.
I get a 3-4MPG better with the A/C off.
Unfortunately this also is causing shaking at the red lights and stop and go.
Luckily the car has not died on me this year.
I have had a couple of times the car stall when the low idle, stop and go.
Very annoying and the only fix is to run the A/C all the time.
Luckily I no longer live in Chicago!
California winters for me please.
I have had the low idle shake since the cars was about a year old.
Gs400 2000 with K/N drop in filter.
The gas mileage is crazy though.
I get a 3-4MPG better with the A/C off.
Unfortunately this also is causing shaking at the red lights and stop and go.
Luckily the car has not died on me this year.
I have had a couple of times the car stall when the low idle, stop and go.
Very annoying and the only fix is to run the A/C all the time.
Luckily I no longer live in Chicago!
California winters for me please.
Thread Starter
Lead Lap
Joined: Apr 2004
Posts: 3,565
Likes: 48
From: Illinois
Exactly. Although new engine mounts might reduce the shaking, it doesn't address the fundamental problem of low idle. And, I'm not so sure that new engine mounts would really help that much in light of Alexulan's post. He has had the shakes since the car was a year old and I doubt his engine mounts were bad at that time.